import java.io.BufferedReader; import java.io.InputStreamReader; /** * * @author Varun Upadhyay (https://github.com/varunu28) * */ // Driver program public class AnyBaseToDecimal { public static void main (String[] args) throws Exception{ BufferedReader br = new BufferedReader(new InputStreamReader(System.in)); String inp = br.readLine(); int base = Integer.parseInt(br.readLine()); System.out.println("Input in base " + base + " is: " + inp); System.out.println("Decimal value of " + inp + " is: " + convertToDecimal(inp, base)); br.close(); } /** * This method produces a decimal value of any given input number of any base * @param inp_num String of which we need the decimal value and base in integer format * @return string format of the decimal value */ public static String convertToDecimal(String inp_num, int base) { int len = inp_num.length(); int num = 0; int pow = 1; for (int i=len-1; i>=0; i--) { if (valOfChar(inp_num.charAt(i)) >= base) { return "Invalid Number"; } num += valOfChar(inp_num.charAt(i))*pow; pow *= base; } return String.valueOf(num); } /** * This method produces integer value of the input character and returns it * @param c Char of which we need the integer value of * @return integer value of input char */ public static int valOfChar(char c) { if (c >= '0' && c <= '9') { return (int)c - '0'; } else { return (int)c - 'A' + 10; } } }