Compilare: user.cpp: In function ‘int main()’: user.cpp:4:32: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("ceas3.in", "r", stdin);freopen("ceas3.out", "w", stdout); ^ user.cpp:4:66: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("ceas3.in", "r", stdin);freopen("ceas3.out", "w", stdout); ^ user.cpp:6:22: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] int a;scanf("%d", &a);if (feof(stdin)) break;int m = a * 2;int h = m / 60;m = m - h * 60;h = (h + 9) % 12;if (h < 10) printf("0");printf("%d:", h);if (m < 10) printf("0");printf("%d\n", m);} ^