Compilare: user.cpp: In function ‘int main()’: user.cpp:9:9: warning: variable ‘start’ set but not used [-Wunused-but-set-variable] clock_t start; ^ user.cpp: In function ‘void read()’: user.cpp:58:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=0;i<m;i++) ^ user.cpp:59:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j=0;j<n;j++) ^ user.cpp: In function ‘int main()’: user.cpp:49:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("lacusta.out","w",stdout); ^ user.cpp: In function ‘void read()’: user.cpp:56:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("lacusta.in","r",stdin); ^ user.cpp:57:24: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d",&m,&n); ^ user.cpp:60:29: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&a[i][j]); ^