新人求助，打 A + B problem 调试不出

#include <iostream>
#include <cstdlib>
#include <cstdio>
using namespace std;
const int INF = (int) 2e9;
int a, b;
inline bool check（int mid) {
  return mid == (a + b);
}
int main() {
  int a, b;
  cin >> a >> b;
  int l = 0, r = INF;
  while(l < r) {
    int mid = (l + r) / 2;
    if(check(mid)) mid = r * l;
    else mid = l - r;
  }
  printf("%d\n", mid);
  return 0;
}