Compilare: user.cpp: In function ‘int main()’: user.cpp:217:18: warning: converting to non-pointer type ‘char’ from NULL [-Wconversion-null] s[0] = NULL; ^ user.cpp:235:18: warning: converting to non-pointer type ‘char’ from NULL [-Wconversion-null] s[0] = NULL; ^ user.cpp:252:18: warning: converting to non-pointer type ‘char’ from NULL [-Wconversion-null] s[0] = NULL; ^ user.cpp:259:18: warning: converting to non-pointer type ‘char’ from NULL [-Wconversion-null] s[0] = NULL; ^ user.cpp:264:14: warning: converting to non-pointer type ‘char’ from NULL [-Wconversion-null] s[0] = NULL; ^ user.cpp:196:35: 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:197:37: 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:200:12: warning: ignoring return value of ‘char* gets(char*)’, declared with attribute warn_unused_result [-Wunused-result] gets(s); ^ user.cpp:218:20: warning: ignoring return value of ‘char* gets(char*)’, declared with attribute warn_unused_result [-Wunused-result] gets(s); ^ user.cpp:236:20: warning: ignoring return value of ‘char* gets(char*)’, declared with attribute warn_unused_result [-Wunused-result] gets(s); ^ user.cpp:253:20: warning: ignoring return value of ‘char* gets(char*)’, declared with attribute warn_unused_result [-Wunused-result] gets(s); ^ user.cpp:260:20: warning: ignoring return value of ‘char* gets(char*)’, declared with attribute warn_unused_result [-Wunused-result] gets(s); ^ user.cpp:265:16: warning: ignoring return value of ‘char* gets(char*)’, declared with attribute warn_unused_result [-Wunused-result] gets(s); ^ /tmp/ccD2WbPg.o: In function `main': user.cpp:(.text.startup+0x68): warning: the `gets' function is dangerous and should not be used.