就是卡cin，有这个必要吗

#include <bits/stdc++.h>
using namespace std;

typedef long long LL;

LL gcd(LL x, LL y) {
    if (y == 0) return x;
    return gcd(y, x % y);
}

int main() {
    int k;
    cin >> k;
    while (k--) {
        char s[200];
        scanf("%s", s);
        int a = 0, b = 0, pos;
        for (int i = 0; i < strlen(s); i++) {
        	if (s[i] == '/') pos = i;
		}
        for (int i = 0; i < strlen(s); i++) {
            if (i < pos) {
                a = a * 10 + s[i] - '0';
            } else if (i > pos) {
                b = b * 10 + s[i] - '0';
            }
        }
        
        LL c = gcd(a, b);
        cout << a / c << "/" << b / c << "\n";
    }
    return 0;
}