十六进制转十进制

package com.studyJava.stringStudy;

import java.util.Scanner;

public class hexToDecimal {

public static void main(String[] args){
Scanner input =new Scanner(System.in);
String str =input.nextLine();
int result = hexToDecimal(str.toUpperCase());
System.out.println(str+"对应的十进制数是：" + result);
}

private static int hexToDecimal(String str) {
int sum =0;
for(int i =0 ;i<str.length();i++){
char ch = str.charAt(i);
try {
sum = sum * 16 + decimal(ch);
} catch (Exception e) {
e.printStackTrace();
}
}
return sum;
}

private static int decimal(char ch) throws Exception {
if(ch>='A'&&ch<='F'){
return 10 +ch -'A';
}else if(ch>='0'&&ch<='9'){
return ch -'0';
}else{
throw new Exception("十六进制数不合理，请重新输入");
}
}
}