Finding inverse

input/code.cpp: In function 'void Test()':
input/code.cpp:21:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   21 |     freopen("temp\\in.txt", "r", stdin);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~

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

const int N=10005;

int ExGCD(int a, int b, int& x, int& y) 
{
    if (b == 0) 
    {
        x = 1, y = 0;
        return a;
    }
    int d = ExGCD(b, a % b, y, x);
    y -= a / b * x;
    return d;
}

void Test()
{
    freopen("temp\\in.txt", "r", stdin);
}
int main()
{
    // Test();
    int a, b, x, y;
    cin >> a >> b;

    int d = ExGCD(a, b, x, y);
    if(d == 1)
        cout << (x % b + b) % b;
    else
        cout << -1;

    return 0;
}

Test 1

Verdict: ACCEPTED

Test 2

Verdict: ACCEPTED

Test 3

Verdict: ACCEPTED

Test 4

Verdict: ACCEPTED

Test 5

Verdict: ACCEPTED

Test 6

Verdict: ACCEPTED

Test 7

Verdict: ACCEPTED

Test 8

Verdict: ACCEPTED

Test 9

Verdict: ACCEPTED

Test 10

Verdict: ACCEPTED

Test 11

Verdict: ACCEPTED

Test 12

Verdict: ACCEPTED

Test 13

Verdict: ACCEPTED

Test 14

Verdict: ACCEPTED