Compilare: user.cpp: In function ‘int main()’: user.cpp:29:40: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen ("culegere.in", "r", stdin); ^ user.cpp:30:42: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen ("culegere.out", "w", stdout); ^ user.cpp:33:42: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf ("%d %d %d %d", &n, &m, &k, &e); ^ user.cpp:48:58: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf ("%d %d %d %d %d", &op, &xx, &yy, &st, &en); ^ user.cpp:51:19: warning: ignoring return value of ‘char* gets(char*)’, declared with attribute warn_unused_result [-Wunused-result] gets (str); ^ /tmp/ccK8oE8y.o: In function `main': user.cpp:(.text.startup+0x154): warning: the `gets' function is dangerous and should not be used.