Compilare: user.cpp: In function ‘int main()’: user.cpp:24:33: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] {for(k=0;k<v[c[j]].size();k++) ^ user.cpp:37:25: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(k=0;k<v[j].size();k++) ^ user.cpp:7:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] {freopen ("bellmanford.in","r",stdin); ^ user.cpp:8:39: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen ("bellmanford.out","w",stdout); ^ user.cpp:10:20: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d",&n,&m); ^ user.cpp:12:30: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] {scanf("%d%d%d",&k,&x,&q); ^