Given a number in a given base, convert it into another target base.
Examples
Input : Number = "123"
Source Base = 8
Target Base = 10
Output : 83
3 * 1 + 2 * 8 + 1 * 64 = 83
Input : Number = "110"
Source Base = 2
Target Base = 10
Output : 6
The idea is to use toString() method present in the Integer wrapper class. We also use partseInt() to parse given string representation of number in a given base.
Java
// Java program to convert one base to otherpublic class MainClass { public static String baseConversion(String number, int sBase, int dBase) { // Parse the number with source radix // and return in specified radix(base) return Integer.toString( Integer.parseInt(number, sBase), dBase); } public static void main(String[] args) { String number = "555"; // Number int sBase = 8; // Source Base Octal int dBase = 10; // Destination Base Decimal System.out.println( "Octal to Decimal: " + baseConversion(number, sBase, dBase)); dBase = 16; // Destination Base Hexadecimal System.out.println( "Octal to Hex: " + baseConversion(number, sBase, dBase)); }} |
Output:
Octal to Decimal: 365 Octal to Hex: 16d
Without using a Predefined method
Java
// Java program to convert one base to otherimport java.io.*;import java.util.*;class Number { private int base; // 2, 8, 10, 16 private String value; // can be of any base private Map<Character, Integer> hexatoDec; // for hexadecimal to decimal conversion private Map<Integer, Character> dectoHex; // for decimal to hexadecimal public Number(String value, int base) { this.value = value; this.base = base; hexatoDec = new HashMap<>(); dectoHex = new HashMap<>(); for (int i = 0; i < 6; i++) { dectoHex.put(10 + i, (char)('A' + i)); hexatoDec.put((char)('A' + i), 10 + i); } } public Number(String value) { // default base 10 this.base = 10; this.value = value; } public String toDecimal() { int sum = 0; int pow = 0; String tempVal = this.value; for (int i = tempVal.length() - 1; i >= 0; i--) { int val = tempVal.charAt(i) - '0'; if (this.base == 16 && hexatoDec.containsKey( tempVal.charAt(i))) { val = hexatoDec.get(tempVal.charAt(i)); } sum += (val) * (Math.pow(this.base, pow++)); } return String.valueOf(sum); } public String toBase(int targetBase) { // take the given number // convert it into decimal // divide the decimal with the target base String val = this.value; // must be in decimal if (this.base != 10) val = toDecimal(); int temp = Integer.parseInt(val); StringBuilder str = new StringBuilder(); while (temp != 0) { int tempValue = temp % targetBase; if (targetBase == 16 && dectoHex.containsKey(tempValue)) { str.insert(0, dectoHex.get(tempValue)); } else { str.insert(0, tempValue); } temp /= targetBase; } return str.toString(); }}class GFG { public static void main(String[] args) { Number n1 = new Number("10AF", 16); System.out.println("Decimal : " + n1.toDecimal()); System.out.println("Octal : " + n1.toBase(8)); System.out.println("Binary : " + n1.toBase(2)); }} |
Output
Decimal : 4271 Octal : 10257 Octal : 1000010101111
