Compilare: user.cpp: In function ‘int main()’: user.cpp:112:20: warning: ISO C++ forbids converting a string constant to ‘char*’ [-Wwrite-strings] Graf g("apm.in"); ^ user.cpp:113:34: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("apm.out","w",stdout); ^ user.cpp: In constructor ‘Graf::Graf(char*)’: user.cpp:78:34: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen(file, "r", stdin); ^ user.cpp:79:29: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d",&N,&M); ^ user.cpp:83:42: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d%d",&n1,&n2,&cost); ^