Compilare: main.cpp: In function 'int main()': main.cpp:36:38: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("sortnet.in", "r", stdin); ^ main.cpp:37:40: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("sortnet.out", "w", stdout); ^ main.cpp:39:29: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d\n", &n, &m); ^ main.cpp:42:63: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("<%d,%d> ", &v[i][j].first, &v[i][j].second); ^