Given some US Currencies, the task is to check if they are valid or not using regular expressions. Rules for the valid Currency are:
- It should always start with “$“.
- It can contain only digits (0 – 9) and at most one dot.
- It should not contain any whitespaces and alphabets.
- Comma Separator (‘, ‘) should be there after every three digits interval.
Examples:
Input: “$0.84”
Output: TrueInput: “12345”
Output: False
Explanation: “$” is missing in the starting.
Approach: The problem can be solved based on the following idea:
Create a regex pattern to validate the number as written below:
regex = “^\$([0-9]{1, 3}(\, [0-9]{3})*|([0-9]+))(\.[0-9]{2})?$”OR
regex=”^\$(\d{1, 3}(\, \d{3})*|(\d+))(\.\d{2})?$“
Where,
- ^ : Represents, beginning of the string
- \$ : Should always start from $
- \d : Digits should be there
- \. : dot can be present or not
- \d{2} : Only digits are allowed after dot
Follow the below steps to implement the idea:
- Create a regex expression for US Currency.
- Use Pattern class to compile the regex formed.
- Use the matcher function to check whether the US Currency is valid or not.
- If it is valid, return true. Otherwise, return false.
Below is the implementation of the above approach.
C++
// C++ program to validate the// US CURRENCY using Regular// Expression#include <bits/stdc++.h>#include <regex>using namespace std;// Function to validate the// US CURRENCYstring isValid_USCurrency(string str){ // Regex to check valid // US CURRENCY. const regex pattern( "^\\$(\\d{1, 3}(\\, \\d{3})*|(\\d+))(\\.\\d{2})?$"); // If the str // is empty return false if (str.empty()) { return "false"; } // Return true if the str // matched the ReGex if (regex_match(str, pattern)) { return "true"; } else { return "false"; }}// Driver Codeint main(){ // Test Case 1: string str1 = "$123458"; cout << isValid_USCurrency(str1) << endl; // Test Case 2: string str2 = "$1, 234, 567.89"; cout << isValid_USCurrency(str2) << endl; // Test Case 3: string str3 = "$0.84"; cout << isValid_USCurrency(str3) << endl; // Test Case 4: string str4 = "$12, 3456.01"; cout << isValid_USCurrency(str4) << endl; // Test Case 5: string str5 = "$1.234"; cout << isValid_USCurrency(str5) << endl; return 0;} |
Java
// Java program to validate the// US Currency using Regular Expressionimport java.util.regex.*;class GFG { // Function to validate the // US Currency public static boolean isValid_USCurrency(String str) { // Regex to check valid US Currency String regex = "^\\$(\\d{1, 3}(\\, \\d{3})*|(\\d+))(\\.\\d{2})?$"; // Compile the ReGex Pattern p = Pattern.compile(regex); // If the str is empty return false if (str == null) { return false; } // Pattern class contains matcher() // method to find matching between // given str using regex. Matcher m = p.matcher(str); // Return if the str // matched the ReGex return m.matches(); } // Driver Code. public static void main(String args[]) { // Test Case 1: String str1 = "$123458"; System.out.println(isValid_USCurrency(str1)); // Test Case 2: String str2 = "$1, 234, 567.89"; System.out.println(isValid_USCurrency(str2)); // Test Case 3: String str3 = "$0.84"; System.out.println(isValid_USCurrency(str3)); // Test Case 4: String str4 = "$12, 3456.01"; System.out.println(isValid_USCurrency(str4)); // Test Case 5: String str5 = "$1.234"; System.out.println(isValid_USCurrency(str5)); }} |
Python3
# Python3 program to validate# US Currency using Regular Expressionimport re# Function to validate# US Currencydef isValid_USCurrency(str): # Regex to check valid US Currency regex = "^\\$(\\d{1, 3}(\\, \\d{3})*|(\\d+))(\\.\\d{2})?$" # Compile the ReGex p = re.compile(regex) # If the string is empty # return false if (str == None): return "false" # Return if the string # matched the ReGex if(re.search(p, str)): return "true" else: return "false"# Driver codeif __name__ == '__main__': # Test Case 1: str1 = "$123458" print(isValid_USCurrency(str1)) # Test Case 2: str2 = "$1, 234, 567.89" print(isValid_USCurrency(str2)) # Test Case 3: str3 = "$0.84" print(isValid_USCurrency(str3)) # Test Case 4: str4 = "$12, 3456.01" print(isValid_USCurrency(str4)) # Test Case 5: str5 = "$1.234" print(isValid_USCurrency(str5)) |
C#
// C# program to validate the// US Currency using Regular Expressionusing System;using System.Text.RegularExpressions;public class GFG { // Function to validate the // US Currency public static bool isValid_USCurrency(string str) { // Regex to check valid US Currency string regex = "^\\$(\\d{1, 3}(\\, \\d{3})*|(\\d+))(\\.\\d{2})?$"; // Compile the ReGex Regex p = new Regex(regex); // If the str is empty return false if (str == null) { return false; } // Pattern class contains matcher() // method to find matching between // given str using regex. Match m = p.Match(str); // Return if the str // matched the ReGex return m.Success; } // Driver Code. public static void Main() { // Test Case 1: string str1 = "$123458"; Console.WriteLine(isValid_USCurrency(str1)); // Test Case 2: string str2 = "$1, 234, 567.89"; Console.WriteLine(isValid_USCurrency(str2)); // Test Case 3: string str3 = "$0.84"; Console.WriteLine(isValid_USCurrency(str3)); // Test Case 4: string str4 = "$12, 3456.01"; Console.WriteLine(isValid_USCurrency(str4)); // Test Case 5: string str5 = "$1.234"; Console.WriteLine(isValid_USCurrency(str5)); }}// This code is contributed by Pushpesh Raj. |
Javascript
// Javascript program to validate// US Currency using Regular Expression// Function to validate the// US Currencyfunction isValid_USCurrency(str) { // Regex to check valid // US Currency let regex = new RegExp(/^\$(\d{1, 3}(\, \d{3})*|(\d+))(\.\d{2})?$/); // if str // is empty return false if (str == null) { return "false"; } // Return true if the str // matched the ReGex if (regex.test(str) == true) { return "true"; } else { return "false"; }}// Driver Code// Test Case 1:let str1 = "$123458";console.log(isValid_USCurrency(str1));// Test Case 2:let str2 = "$1, 234, 567.89";console.log(isValid_USCurrency(str2));// Test Case 3:let str3 = "$0.84";console.log(isValid_USCurrency(str3));// Test Case 4:let str4 = "$12, 3456.01";console.log(isValid_USCurrency(str4));// Test Case 5:let str5 = "$1.234";console.log(isValid_USCurrency(str5)); |
Output
true true true false false
Time Complexity: O(N) for each test case, where N is the length of the given string.
Auxiliary Space: O(1)
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