Compilare: user.cpp: In function ‘int main()’: user.cpp:89:34: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("radio2.in", "r", stdin); ^ user.cpp:90:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("radio2.out", "w", stdout); ^ user.cpp:92:37: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d%d%d\n", &N, &M, &L, &K); ^ user.cpp:93:13: warning: ignoring return value of ‘char* gets(char*)’, declared with attribute warn_unused_result [-Wunused-result] gets(x + 1); ^ user.cpp:100:17: warning: ignoring return value of ‘char* gets(char*)’, declared with attribute warn_unused_result [-Wunused-result] gets(word + 1); ^ /tmp/ccwADwIe.o: In function `main': user.cpp:(.text.startup+0x85): warning: the `gets' function is dangerous and should not be used.