Compilare: user.cpp: In function ‘int main()’: user.cpp:218:18: warning: converting to non-pointer type ‘char’ from NULL [-Wconversion-null] s[0] = NULL; ^ user.cpp:230:18: warning: converting to non-pointer type ‘char’ from NULL [-Wconversion-null] s[0] = NULL; ^ user.cpp:242:18: warning: converting to non-pointer type ‘char’ from NULL [-Wconversion-null] s[0] = NULL; ^ user.cpp:251:18: warning: converting to non-pointer type ‘char’ from NULL [-Wconversion-null] s[0] = NULL; ^ user.cpp:258:14: warning: converting to non-pointer type ‘char’ from NULL [-Wconversion-null] s[0] = NULL; ^ user.cpp:202:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("zeap.in", "r", stdin); ^ user.cpp:203:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("zeap.out", "w", stdout); ^ user.cpp:207:12: warning: ignoring return value of ‘char* gets(char*)’, declared with attribute warn_unused_result [-Wunused-result] gets(s); ^ user.cpp:219:20: warning: ignoring return value of ‘char* gets(char*)’, declared with attribute warn_unused_result [-Wunused-result] gets(s); ^ user.cpp:231:20: warning: ignoring return value of ‘char* gets(char*)’, declared with attribute warn_unused_result [-Wunused-result] gets(s); ^ user.cpp:243:20: warning: ignoring return value of ‘char* gets(char*)’, declared with attribute warn_unused_result [-Wunused-result] gets(s); ^ user.cpp:252:20: warning: ignoring return value of ‘char* gets(char*)’, declared with attribute warn_unused_result [-Wunused-result] gets(s); ^ user.cpp:259:16: warning: ignoring return value of ‘char* gets(char*)’, declared with attribute warn_unused_result [-Wunused-result] gets(s); ^ /tmp/ccEBZw8l.o: In function `main': user.cpp:(.text.startup+0x68): warning: the `gets' function is dangerous and should not be used.