Compilare: user.cpp: In function ‘int main()’: user.cpp:57:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("lcdr.in", "r", stdin); ^ user.cpp:58:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("lcdr.out", "w", stdout); ^ user.cpp:61:34: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d%d\n", &n, &m, &q); ^ user.cpp:63:22: warning: ignoring return value of ‘char* gets(char*)’, declared with attribute warn_unused_result [-Wunused-result] gets(tmp + 1); ^ user.cpp:76:64: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d%d%d", &Q[i].L, &Q[i].C, &Q[i].L1, &Q[i].L2); ^ /tmp/cc4uDkHC.o: In function `main': user.cpp:(.text.startup+0x94): warning: the `gets' function is dangerous and should not be used.