Compilare: user.cpp: In function ‘void prim(int, int, int)’: user.cpp:33: warning: unused variable ‘cost’ user.cpp: In function ‘int main()’: user.cpp:59: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result user.cpp:60: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result user.cpp:63: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result user.cpp:70: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result