Compilare: user.cpp: In function ‘int main()’: user.cpp:10:13: warning: unused variable ‘ans’ [-Wunused-variable] int l,n,ans=0,t; ^ user.cpp:8:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("cifra.in", "r", stdin); ^ user.cpp:9:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("cifra.out", "w", stdout); ^ user.cpp:13:27: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] for (scanf("%d\n", &t);t>0;--t) ^ user.cpp:15:16: warning: ignoring return value of ‘char* gets(char*)’, declared with attribute warn_unused_result [-Wunused-result] gets(s); ^ /tmp/ccskO7al.o: In function `main': user.cpp:(.text.startup+0x117): warning: the `gets' function is dangerous and should not be used.