Compilare: main.cpp: In function 'int main()': main.cpp:43:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j = 1 ; j < s.size() - 1 ; j++) ~~^~~~~~~~~~~~~~ main.cpp:23:37: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("dreptpal.in","r",stdin); ^ main.cpp:24:39: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("dreptpal.out","w",stdout); ^ main.cpp:25:24: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d",&m,&n); ^ main.cpp:29:33: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&a[i][j]); ^