Given a string, count the number of words in it. The words are separated by the following characters: space (‘ ‘) or new line (‘\n’) or tab (‘\t’) or a combination of these.
Method 1: The idea is to maintain two states: IN and OUT. The state OUT indicates that a separator is seen. State IN indicates that a word character is seen. We increment word count when previous state is OUT and next character is a word character.
C
/* C program to count no of words from given input string. */#include <stdio.h>#define OUT 0#define IN 1// returns number of words in strunsigned countWords(char *str){ int state = OUT; unsigned wc = 0; // word count // Scan all characters one by one while (*str) { // If next character is a separator, set the // state as OUT if (*str == ' ' || *str == '\n' || *str == '\t') state = OUT; // If next character is not a word separator and // state is OUT, then set the state as IN and // increment word count else if (state == OUT) { state = IN; ++wc; } // Move to next character ++str; } return wc;}// Driver program to test above functionsint main(void){ char str[] = "One two three\n four\tfive "; printf("No of words : %u", countWords(str)); return 0;} |
C++
/* C++ program to count no of wordsfrom given input string. */#include <bits/stdc++.h>using namespace std;#define OUT 0#define IN 1// returns number of words in strunsigned countWords(char *str){ int state = OUT; unsigned wc = 0; // word count // Scan all characters one by one while (*str) { // If next character is a separator, set the // state as OUT if (*str == ' ' || *str == '\n' || *str == '\t') state = OUT; // If next character is not a word separator and // state is OUT, then set the state as IN and // increment word count else if (state == OUT) { state = IN; ++wc; } // Move to next character ++str; } return wc;}// Driver codeint main(void){ char str[] = "One two three\n four\tfive "; cout<<"No of words : "<<countWords(str); return 0;}// This is code is contributed by rathbhupendra |
Java
/* Java program to count no of wordsfrom given input string. */public class GFG { static final int OUT = 0; static final int IN = 1; // returns number of words in str static int countWords(String str) { int state = OUT; int wc = 0; // word count int i = 0; // Scan all characters one by one while (i < str.length()) { // If next character is a separator, set the // state as OUT if (str.charAt(i) == ' ' || str.charAt(i) == '\n' || str.charAt(i) == '\t') state = OUT; // If next character is not a word separator // and state is OUT, then set the state as IN // and increment word count else if (state == OUT) { state = IN; ++wc; } // Move to next character ++i; } return wc; } // Driver program to test above functions public static void main(String args[]) { String str = "One two three\n four\tfive "; System.out.println("No of words : " + countWords(str)); }}// This code is contributed by Sumit Ghosh |
Python3
# Python3 program to count words# in a given stringOUT = 0IN = 1# Returns number of words in stringdef countWords(string): state = OUT wc = 0 # Scan all characters one by one for i in range(len(string)): # If next character is a separator, # set the state as OUT if (string[i] == ' ' or string[i] == '\n' or string[i] == '\t'): state = OUT # If next character is not a word # separator and state is OUT, then # set the state as IN and increment # word count elif state == OUT: state = IN wc += 1 # Return the number of words return wc# Driver Codestring = "One two three\n four\tfive "print("No. of words : " + str(countWords(string)))# This code is contributed by BHAVYA JAIN |
C#
// C# program to count no of words// from given input string.using System;class GFG { static int OUT = 0; static int IN = 1; // returns number of words in str static int countWords(String str) { int state = OUT; int wc = 0; // word count int i = 0; // Scan all characters one // by one while (i < str.Length) { // If next character is a separator, // set the state as OUT if (str[i] == ' ' || str[i] == '\n'|| str[i] == '\t') state = OUT; // If next character is not a word // separator and state is OUT, then // set the state as IN and increment // word count else if (state == OUT) { state = IN; ++wc; } // Move to next character ++i; } return wc; } // Driver program to test above functions public static void Main() { String str = "One two three\n four\tfive "; Console.WriteLine("No of words : " + countWords(str)); }}// This code is contributed by Sam007. |
PHP
<?php// PHP program to count no of// words from given input string$OUT = 0;$IN = 1;// returns number of words in strfunction countWords($str){ global $OUT, $IN; $state = $OUT; $wc = 0; // word count $i = 0; // Scan all characters one by one while ($i < strlen($str)) { // If next character is // a separator, set the // state as OUT if ($str[$i] == " " || $str[$i] == "\n" || $str[$i] == "\t") $state = $OUT; // If next character is not a // word separator and state is // OUT, then set the state as // IN and increment word count else if ($state == $OUT) { $state = $IN; ++$wc; } // Move to next character ++$i; } return $wc;}// Driver Code$str = "One two three\n four\tfive ";echo "No of words : " . countWords($str);// This code is contributed// by ChitraNayal?> |
Javascript
<script>// javascript program to count no of words// from given input string. var OUT = 0; var IN = 1; // returns number of words in str function countWords( str) { var state = OUT; var wc = 0; // word count var i = 0; // Scan all characters one // by one while (i < str.length) { // If next character is a separator, // set the state as OUT if (str[i] == ' ' || str[i] == '\n'|| str[i] == '\t') state = OUT; // If next character is not a word // separator and state is OUT, then // set the state as IN and increment // word count else if (state == OUT) { state = IN; ++wc; } // Move to next character ++i; } return wc; } // Driver program to test above functions var str = "One two three\n four\tfive "; document.write("No of words : " + countWords(str));// This code is contributed by bunnyram19.</script> |
Output
No of words : 5
Time complexity: O(n)
Auxiliary Space: O(1)
This article is compiled by Aarti_Rathi and Narendra Kangralkar. Please write comments if you find anything incorrect, or you want to share more information about the topic discussed above.
Method 2: using String.split() method
- Get the string to count the total number of words.
- Check if the string is empty or null then return 0.
- Use split() method of String class to split the string on whitespaces.
- The split() method breaks the given string around matches of the given regular expression and returns an array of string.
- The length of the array is the number of words in the given string.
- Now, print the result.
Below is the implementation of the above approach:
C
// C program to count total// number of words in the string#include <stdio.h>#include <string.h>// Function to count total number// of words in the stringint countWords(char str[]){ // Check if the string is null // or empty then return zero if (strlen(str) == 0) { return 0; } // Splitting the string around // matches of the given regular // expression char* token; char* delim = " \n\t"; token = strtok(str, delim); int count = 0; while (token != NULL) { count++; token = strtok(NULL, delim); } // Return number of words // in the given string return count;}int main(){ // Given String str char str[] = "One two three\n four\tfive "; // Print the result printf("No of words : %d", countWords(str)); return 0;} |
C++
// C++ program to count total// number of words in the string#include <bits/stdc++.h>using namespace std;// Function to count total number// of words in the stringint countWords(string str){ // Check if the string is null // or empty then return zero if (str.size() == 0) { return 0; } // Splitting the string around // matches of the given regular // expression vector<string> words; string temp = ""; for (int i = 0; i < str.size(); i++) { if (str[i] == ' ') { words.push_back(temp); temp = ""; } else { temp += str[i]; } } int count = 1; for (int i = 0; i < words.size(); i++) { if (words[i].size() != 0) count++; } // Return number of words // in the given string return count;}int main(){ // Given String str string str = "One two three\n four\tfive "; // Print the result cout << "No of words : " << countWords(str); return 0;}// This code is contributed by akashish__ |
Java
// Java program to count total// number of words in the stringimport java.io.*;class GFG{ // Function to count total number // of words in the string public static int countWords(String str) { // Check if the string is null // or empty then return zero if (str == null || str.isEmpty()) return 0; // Splitting the string around // matches of the given regular // expression String[] words = str.split("\\s+"); // Return number of words // in the given string return words.length; } // Driver Code public static void main(String args[]) { // Given String str String str = "One two three\n four\tfive "; // Print the result System.out.println("No of words : " + countWords(str)); }}// This code is contributed by Prashant Srivastava |
Python3
# Python program to count total# number of words in the stringdef countWords(s): # Check if the string is null # or empty then return zero if s.strip() == "": return 0 # Splitting the string words = s.split() return len(words)if __name__ == "__main__": s = "One two three\n four\tfive " print("No of words : ", countWords(s)) |
C#
// Include namespace systemusing System;// C# program to count total// number of words in the stringpublic class GFG{ // Function to count total number // of words in the string public static int countWords(String str) { // Check if the string is null // or empty then return zero if (str == null || str.Length == 0) { return 0; } // Splitting the string around // matches of the given regular // expression String[] words = str.Split(" "); int count = 1; for(int i=0;i<words.Length;i++){ if(words[i].Length!=0) count++; } // Return number of words // in the given string return count; } // Driver Code public static void Main(String[] args) { // Given String str var str = "One two three\n four\tfive "; // Print the result Console.WriteLine("No of words : " + GFG.countWords(str).ToString()); }} |
Javascript
// Javascript program to count total// number of words in the string// Function to count total number// of words in the stringfunction countWords(str){ // Check if the string is null // or empty then return zero if (str.length == 0) { return 0; } // Splitting the string around // matches of the given regular // expression words = []; var temp = ""; for (var i = 0; i < str.length; i++) { if (str[i] == " ") { words.push(temp); temp = ""; } else { temp += str[i]; } } var count = 1; for (var i = 0; i < words.length; i++) { if (words[i].length != 0) count++; } // Return number of words // in the given string return count;}// Driver code // Given String str var str = "One two three\n four\tfive "; // Print the result console.log("No of words : " +countWords(str)); // This code is contributed by Abhijeet Kumar(abhijeet19403) |
Output
No of words : 5
Time Complexity: O(N)
Auxiliary Space: O(1)
Method 3: using StringTokenizer.countTokens() method
- Get the string to count the total number of words.
- Check if the string is empty or null then return 0.
- Create a StringTokenizer with the given string passed as a parameter.
- Count the total number of words in the given string using the countTokens() method.
- Now, print the result.
Below is the implementation of the above approach:
C
// C program to count total// number of words in the string#include <stdio.h>#include <string.h>// Function to count total number// of words in the stringint countWords(char* s){ // Check if the string is null // or empty then return zero if (s == NULL || strlen(s) == 0) return 0; int count = 0; char* token = strtok(s, "/"); while (token != NULL) { ++count; token = strtok(NULL, "/"); } return count;}int main(){ char str[] = "One/ two / three/n four/tfive "; // Print the result printf("No of words: %d\n", countWords(str)); return 0;} |
C++
// C++ program to count total// number of words in the string#include <bits/stdc++.h>using namespace std;// Function to count total number// of words in the stringint countWords(string s){ // Check if the string is null // or empty then return zero if (s.empty()) return 0; istringstream is(s); int count = 0; string line; while (getline(is, line, '/')) ++count; return count;}int main(){ string str = "One/ two / three/n four/tfive "; // Print the result cout << "No of words: " << countWords(str) << endl;} |
Java
// Java program to count total// number of words in the stringimport java.util.StringTokenizer;class GFG{ // Function to count total number // of words in the string public static int countWords(String str) { // Check if the string is null // or empty then return zero if (str == null || str.isEmpty()) return 0; // Create a StringTokenizer with the // given string passed as a parameter StringTokenizer tokens = new StringTokenizer(str); // Return the number of words // in the given string using // countTokens() method return tokens.countTokens(); } // Driver Code public static void main(String args[]) { // Given String str String str = "One two three\n four\tfive "; // Print the result System.out.println("No of words: " + countWords(str)); }}// This code is contributed by Prashant Srivastava |
Python3
def count_words(s): # Check if the string is null or empty then return zero if not s: return 0 count = 0 lines = s.split("/") for line in lines: # Ignore empty lines if line.strip(): count += 1 return counts = "One/ two / three/n four/tfive "print("No of words:", count_words(s))# This code is contributed by divyansh2212 |
C#
// C# program to count total// number of words in the stringusing System;class GFG{ // Function to count total number // of words in the string public static int countWords(String str) { // Check if the string is null // or empty then return zero if (string.IsNullOrEmpty(str)) return 0; // Create a String Token with the // given string passed as a parameter string[] tokens = str.Split(' '); // Return the number of words // in the given string using // Length method return tokens.Length; } // Driver Code public static void Main() { // Given String str string str = "One two three\n four\tfive "; // Print the result Console.Write("No of words: " + countWords(str)); }}// This code is contributed by Pushpesh Raj |
Javascript
// JavaScript program to count total// number of words in the string// Function to count total number// of words in the stringfunction countWords(s){ // Check if the string is null // or empty then return zero if (s.length === 0) return 0; const lines = s.split("/"); return lines.length;}const str = "One/ two / three/n four/tfive ";// Print the resultconsole.log(`No of words: ${countWords(str)}`);// This code is contributed by akashish__ |
Output
No of words: 5
Time Complexity: O(N)
Auxiliary Space : O(1)
Method 4: using Character.isLetter() method
- Get the string to count the total number of words.
- Check if the string is empty or null then return 0.
- Converting the given string into a character array.
- Check if the character is a letter and index of the character array doesn’t equal to the end of the line that means, it is a word and set isWord by true.
- Check if the character is not a letter that means there is a space, then we increment the wordCount by one and set the isWord by false.
- Check for the last word of the sentence and increment the wordCount by one.
- Now, print the result.
Below is the implementation of the above approach:
C
// C program to count total// number of words in the string#include <ctype.h>#include <stdio.h>// Function// To count total number// of words in the stringint countWords(char* str, int n){ // Check if the string is null // or empty then return zero if (n == 0) { return 0; } int wordCount = 0; int isWord = 0; int endOfLine = n - 1; for (int i = 0; i < n; i++) { // Check if the character is a letter // and index of character array doesn't // equal to end of line that means, it is // a word and set isWord by true if (isalpha(str[i]) && i != endOfLine) { isWord = 1; } // Check if the character is not a letter // that means there is a space, then we // increment the wordCount by one and set // the isWord by false else if (!isalpha(str[i]) && isWord) { wordCount++; isWord = 0; } // Check for the last word of the // sentence and increment the wordCount // by one else if (isalpha(str[i]) && i == endOfLine) { wordCount++; } } // Return the total number of // words in the string return wordCount;}// Driver codeint main(){ char str[] = "One two three\n four\tfive "; int n = (sizeof(str) / sizeof(char)) - 1; printf("No of words : %d", countWords(str, n)); return 0;} |
C++
// C++ program to count total// number of words in the string#include <bits/stdc++.h>using namespace std;// Function// To count total number// of words in the stringint countWords(char* str, int n){ // Check if the string is null // or empty then return zero if (n == 0) { return 0; } int wordCount = 0; bool isWord = false; int endOfLine = n - 1; for (int i = 0; i < n; i++) { // Check if the character is a letter // and index of character array doesn't // equal to end of line that means, it is // a word and set isWord by true if (isalpha(str[i]) && i != endOfLine) { isWord = true; } // Check if the character is not a letter // that means there is a space, then we // increment the wordCount by one and set // the isWord by false else if (!isalpha(str[i]) && isWord) { wordCount++; isWord = false; } // Check for the last word of the // sentence and increment the wordCount // by one else if (isalpha(str[i]) && i == endOfLine) { wordCount++; } } // Return the total number of // words in the string return wordCount;}// Driver codeint main(){ char str[] = "One two three\n four\tfive "; int n = (sizeof(str) / sizeof(char)) - 1; cout << "No of words : " << countWords(str, n); return 0;}// This is code is contributed by Aarti_Rathi |
Java
// Java program to count total// number of words in the stringimport java.io.*;class GFG{ // Function to count total number // of words in the string public static int countWords(String str) { // Check if the string is null // or empty then return zero if(str == null || str.isEmpty()) return 0; int wordCount = 0; boolean isWord = false; int endOfLine = str.length() - 1; // Converting the given string // into a character array char[] ch = str.toCharArray(); for (int i = 0; i < ch.length; i++) { // Check if the character is a letter // and index of character array doesn't // equal to end of line that means, it is // a word and set isWord by true if (Character.isLetter(ch[i]) && i != endOfLine) isWord = true; // Check if the character is not a letter // that means there is a space, then we // increment the wordCount by one and set // the isWord by false else if (!Character.isLetter(ch[i]) && isWord) { wordCount++; isWord = false; } // Check for the last word of the // sentence and increment the wordCount // by one else if (Character.isLetter(ch[i]) && i == endOfLine) wordCount++; } // Return the total number of // words in the string return wordCount; } // Driver Code public static void main(String args[]) { // Given String str String str = "One two three\n four\tfive "; // Print the result System.out.println("No of words : " + countWords(str)); }}// This code is contributed by Prashant Srivastava |
Python3
# Python program to count total# number of words in the string# Function to count total number# of words in the stringdef countWords(Str): # Check if the string is null # or empty then return zero if(Str == None or len(Str) == 0): return 0 wordCount = 0 isWord = False endOfLine = len(Str) - 1 # Converting the given string # into a character array ch = list(Str) for i in range(len(ch)): # Check if the character is a letter # and index of character array doesn't # equal to end of line that means, it is # a word and set isWord by true if(ch[i].isalpha() and i != endOfLine): isWord = True # Check if the character is not a letter # that means there is a space, then we # increment the wordCount by one and set # the isWord by false elif(not ch[i].isalpha() and isWord): wordCount += 1 isWord = False # Check for the last word of the # sentence and increment the wordCount # by one elif(ch[i].isalpha() and i == endOfLine): wordCount += 1 # Return the total number of # words in the string return wordCount# Driver Code# Given String strStr = "One two three\n four\tfive "# Print the resultprint("No of words :", countWords(Str))# This code is contributed by rag2127 |
C#
// C# program to count total// number of words in the stringusing System;public class GFG{ // Function to count total number // of words in the string static int countWords(String str) { // Check if the string is null // or empty then return zero if(str == null) { return 0; } int wordCount = 0; bool isWord = false; int endOfLine = str.Length - 1; // Converting the given string // into a character array char[] ch = str.ToCharArray(); for (int i = 0; i < ch.Length; i++) { // Check if the character is a letter // and index of character array doesn't // equal to end of line that means, it is // a word and set isWord by true if (Char.IsLetter(ch[i]) && i != endOfLine) { isWord = true; } // Check if the character is not a letter // that means there is a space, then we // increment the wordCount by one and set // the isWord by false else if (!Char.IsLetter(ch[i]) && isWord) { wordCount++; isWord = false; } // Check for the last word of the // sentence and increment the wordCount // by one else if (Char.IsLetter(ch[i]) && i == endOfLine) { wordCount++; } } // Return the total number of // words in the string return wordCount; } // Driver Code static public void Main () { // Given String str string str = "One two three\n four\tfive "; // Print the result Console.WriteLine("No of words : " + countWords(str)); }}// This code is contributed by avanitrachhadiya2155 |
Javascript
<script>// Javascript program to count total// number of words in the string// Function to count total number // of words in the stringfunction countWords(str){ // Check if the string is null // or empty then return zero if(str == null || str.length==0) return 0; let wordCount = 0; let isWord = false; let endOfLine = str.length - 1; // Converting the given string // into a character array let ch = str.split(""); for (let i = 0; i < ch.length; i++) { // Check if the character is a letter // and index of character array doesn't // equal to end of line that means, it is // a word and set isWord by true if (isLetter(ch[i]) && i != endOfLine) isWord = true; // Check if the character is not a letter // that means there is a space, then we // increment the wordCount by one and set // the isWord by false else if (!isLetter(ch[i]) && isWord) { wordCount++; isWord = false; } // Check for the last word of the // sentence and increment the wordCount // by one else if (isLetter(ch[i]) && i == endOfLine) wordCount++; } // Return the total number of // words in the string return wordCount;}function isLetter(c) { return c.toLowerCase() != c.toUpperCase();}// Driver Code // Given String strlet str="One two three\n four\tfive ";// Print the resultdocument.write("No of words : " + countWords(str));// This code is contributed by ab2127</script> |
Output
No of words : 5
Time Complexity: O(N)
Auxiliary Space: O(1)
