Compilare: main.cpp: In function 'int main()': main.cpp:61:94: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("fmcm.in","r",stdin),freopen("fmcm.out","w",stdout),scanf("%d%d%d%d",&n,&m,&s,&t); ^ main.cpp:61:94: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] main.cpp:61:94: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] main.cpp:63:109: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d",&x,&y),c[x].push_back(y),c[y].push_back(x),scanf("%d%d",u[x]+y,v[x]+y),v[y][x]=-v[x][y]; ^ main.cpp:63:109: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]