Compilare: user.cpp: In function ‘int main()’: user.cpp:205:18: warning: converting to non-pointer type ‘char’ from NULL [-Wconversion-null] s[0] = NULL; ^ user.cpp:223:18: warning: converting to non-pointer type ‘char’ from NULL [-Wconversion-null] s[0] = NULL; ^ user.cpp:240:18: warning: converting to non-pointer type ‘char’ from NULL [-Wconversion-null] s[0] = NULL; ^ user.cpp:247:18: warning: converting to non-pointer type ‘char’ from NULL [-Wconversion-null] s[0] = NULL; ^ user.cpp:252:14: warning: converting to non-pointer type ‘char’ from NULL [-Wconversion-null] s[0] = NULL; ^ user.cpp:184:35: 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:185:37: 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:188:12: warning: ignoring return value of ‘char* gets(char*)’, declared with attribute warn_unused_result [-Wunused-result] gets(s); ^ user.cpp:206:20: warning: ignoring return value of ‘char* gets(char*)’, declared with attribute warn_unused_result [-Wunused-result] gets(s); ^ user.cpp:224:20: warning: ignoring return value of ‘char* gets(char*)’, declared with attribute warn_unused_result [-Wunused-result] gets(s); ^ user.cpp:241:20: warning: ignoring return value of ‘char* gets(char*)’, declared with attribute warn_unused_result [-Wunused-result] gets(s); ^ user.cpp:248:20: warning: ignoring return value of ‘char* gets(char*)’, declared with attribute warn_unused_result [-Wunused-result] gets(s); ^ user.cpp:253:16: warning: ignoring return value of ‘char* gets(char*)’, declared with attribute warn_unused_result [-Wunused-result] gets(s); ^ /tmp/ccI6tAvQ.o: In function `main': user.cpp:(.text.startup+0x68): warning: the `gets' function is dangerous and should not be used.