WA,VS上运行正确但是在洛谷IDE上却不一样，啥原因

#include<bits/stdc++.h>
using namespace std;
int num(int x) {
    if (x) {
        int t = 0, n = x;
        while (abs(x)) {
            x /= 10;
            t++;
        }
        if (n > 0) {
            return t;
        }
        else {
            return t + 1;
        }
    }
    else {
        return 1;
    }
}
int main() {
    int n;
    cin >> n;
    getchar();
    string s;
    char c;
    for (int i = 0; i < n; i++) {
        int sum[2] = { 0 }, t = 0, a, b;
        getline(cin,s);
        bool f = false;
        for (int j = 0; s[j]; j++) {
            if (s[j] == 'a' || s[j] == 'b' || s[j] == 'c') {
                c = s[j];
                f = true;
            }
            else {
                if (s[j] != ' ') {
                    sum[t] = sum [t] * 10 + s[j] - '0';
                }
                if (s[j] == ' ' || j + 1 == s.size()) {
                    if (f) f = !f;
                    else {
                        t++;
                    }
                }
            }
        }
        a = sum[0], b = sum[1];
        int n1 = num(a), n2 = num(b), n3;
        switch (c) {
        case 'a':
            cout << a << "+" << b << "=" << a + b << endl;
            n3 = num(a + b);
            break;
        case 'b':
            cout << a << "-" << b << "=" << a - b << endl;
            n3 = num(a - b);
            break;
        case 'c':
            cout << a << "*" << b << "=" << a * b << endl;
            n3 = num(a * b);
            break;
        }
        cout << n1 + n2 + n3 + 2 << endl;
    }
    return 0;
}