Compilare: user.c:5:11: warning: conflicting types for built-in function ‘exp’ [enabled by default] long long exp(long long base, long long exp) { ^ user.c: In function ‘main’: user.c:29:15: warning: unused variable ‘b’ [-Wunused-variable] int i, a, b, s, n; ^ user.c:29:12: warning: unused variable ‘a’ [-Wunused-variable] int i, a, b, s, n; ^ user.c:25:12: warning: ignoring return value of ‘freopen’, declared with attribute warn_unused_result [-Wunused-result] freopen("spion.in", "r", stdin); ^ user.c:26:12: warning: ignoring return value of ‘freopen’, declared with attribute warn_unused_result [-Wunused-result] freopen("spion.out", "w", stdout); ^ user.c:31:10: warning: ignoring return value of ‘scanf’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d ",&tsk); ^ user.c:32:9: warning: ignoring return value of ‘gets’, declared with attribute warn_unused_result [-Wunused-result] gets(str); ^ /tmp/cckE9TC8.o: In function `main': user.c:(.text.startup+0x80): warning: the `gets' function is dangerous and should not be used.