Compilare: user.cpp: In function ‘int main()’: user.cpp:14:31: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("ec.in", "r", stdin); //ifstream fi("5-ec.in"); ^ user.cpp:16:24: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d", &n, &k); //fi >> n >> k; ^ user.cpp:21:22: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d", &x); //fi >> x; ^ user.cpp:27:11: warning: ignoring return value of ‘char* gets(char*)’, declared with attribute warn_unused_result [-Wunused-result] gets(ch); ^ user.cpp:29:26: warning: ignoring return value of ‘char* gets(char*)’, declared with attribute warn_unused_result [-Wunused-result] gr2 = false, gets(ch); s = string(ch); ^ user.cpp:23:13: warning: array subscript is below array bounds [-Warray-bounds] f2[x]++; ^ user.cpp:23:13: warning: array subscript is below array bounds [-Warray-bounds] /tmp/cc6j3zv0.o: In function `main': user.cpp:(.text.startup+0x135): warning: the `gets' function is dangerous and should not be used.