【藍橋杯】十六進制轉十進制

十六進制轉十進制

#include<iostream>
#include<math.h>
#include<string.h>
using namespace std;
int main(){
	char s[50];
	cin >> s;
	int n,i;
	n = strlen(s);
	long long sum = 0;
	for( i = 0;i < n;i++){
		if( s[i] >= 'A' && s[i] <= 'Z')
		s[i] = int( s[i] - 'A') + 10 + '0';
		sum += (( s[i] - '0') * (pow(16,n-1-i)));
	}
	cout << sum <<endl;
	return 0;
}