Compilare: user.cpp: In function ‘void royfloyd()’: user.cpp:15:85: warning: suggest parentheses around ‘&&’ within ‘||’ [-Wparentheses] if(a[i][k] && a[k][j] && ( ( a[i][j]> a[i][k]+ a[k][j]) || !a[i][j] && i!=j ) ) a[i][j]=a[i][k]+a[k][j]; ^ user.cpp: In function ‘int main()’: user.cpp:21:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("royfloyd.in", "r", stdin); ^ user.cpp:22:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("royfloyd.out", "w", stdout); ^ user.cpp:24:22: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d\n", &n); ^ user.cpp:27:34: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &a[i][j]); ^