Compilare: user.cpp: In function ‘int main()’: user.cpp:138:11: warning: converting to non-pointer type ‘char’ from NULL [-Wconversion-null] s [1] = NULL; ^ user.cpp:130:42: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen ("dragonball.in", "r", stdin); ^ user.cpp:131:44: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen ("dragonball.out", "w", stdout); ^ user.cpp:133:37: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf ("%d%d%c", &n, &t, &blank); ^ user.cpp:134:13: warning: ignoring return value of ‘char* gets(char*)’, declared with attribute warn_unused_result [-Wunused-result] gets (s); ^ user.cpp:141:17: warning: ignoring return value of ‘char* gets(char*)’, declared with attribute warn_unused_result [-Wunused-result] gets (s); ^ /tmp/ccBPCcCL.o: In function `main': user.cpp:(.text.startup+0x84): warning: the `gets' function is dangerous and should not be used.