Compilare: user.cpp: In function ‘bool cmp(gr, gr)’: user.cpp:25:38: warning: operation on ‘y.gr::a’ may be undefined [-Wsequence-point] x.a = x.a + y.a - (y.a = x.a); ^ user.cpp:26:38: warning: operation on ‘y.gr::b’ may be undefined [-Wsequence-point] x.b = x.b + y.b - (y.b = x.b); ^ user.cpp: In function ‘int main()’: user.cpp:34:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("gramezi.in", "r", stdin); ^ user.cpp:37:22: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d\n", &n); ^ user.cpp:40:41: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d", &g[i].a, &g[i].b); ^ user.cpp:81:40: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("gramezi.out", "w", stdout); ^