Compilare: user.cpp: In function ‘int main()’: user.cpp:45:15: warning: unused variable ‘op’ [-Wunused-variable] int n,m,i,op,x,y,c; ^ user.cpp:45:18: warning: unused variable ‘x’ [-Wunused-variable] int n,m,i,op,x,y,c; ^ user.cpp:45:20: warning: unused variable ‘y’ [-Wunused-variable] int n,m,i,op,x,y,c; ^ user.cpp:45:22: warning: unused variable ‘c’ [-Wunused-variable] int n,m,i,op,x,y,c; ^ user.cpp:43:34: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("apm.in", "r", stdin); ^ user.cpp:44:36: 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:46:27: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d", &n, &m); ^ user.cpp:52:68: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d %d", &edges[i].x, &edges[i].y, &edges[i].cost); ^