54 lines
1.7 KiB
Java
54 lines
1.7 KiB
Java
package Conversions;
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/**
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* @author Varun Upadhyay (https://github.com/varunu28)
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*/
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// Driver program
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public class AnyBaseToDecimal {
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public static void main(String[] args) {
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assert convertToDecimal("1010", 2) == Integer.valueOf("1010", 2);
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assert convertToDecimal("777", 8) == Integer.valueOf("777", 8);
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assert convertToDecimal("999", 10) == Integer.valueOf("999", 10);
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assert convertToDecimal("ABCDEF", 16) == Integer.valueOf("ABCDEF", 16);
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assert convertToDecimal("XYZ", 36) == Integer.valueOf("XYZ", 36);
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}
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/**
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* Convert any radix to decimal number
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*
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* @param s the string to be convert
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* @param radix the radix
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* @return decimal of bits
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* @throws NumberFormatException if {@code bits} or {@code radix} is invalid
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*/
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public static int convertToDecimal(String s, int radix) {
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int num = 0;
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int pow = 1;
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for (int i = s.length() - 1; i >= 0; i--) {
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int digit = valOfChar(s.charAt(i));
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if (digit >= radix) {
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throw new NumberFormatException("For input string " + s);
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}
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num += valOfChar(s.charAt(i)) * pow;
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pow *= radix;
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}
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return num;
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}
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/**
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* Convert character to integer
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*
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* @param c the character
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* @return represented digit of given character
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* @throws NumberFormatException if {@code ch} is not UpperCase or Digit character.
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*/
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public static int valOfChar(char c) {
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if (!(Character.isUpperCase(c) || Character.isDigit(c))) {
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throw new NumberFormatException("invalid character :" + c);
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}
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return Character.isDigit(c) ? c - '0' : c - 'A' + 10;
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}
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}
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