Compilare: user.cpp: In function ‘int main()’: user.cpp:7:31: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("sr.in","r",stdin); ^ user.cpp:8:33: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("sr.out","w",stdout); ^ user.cpp:9:12: warning: ignoring return value of ‘char* gets(char*)’, declared with attribute warn_unused_result [-Wunused-result] gets(a); gets(b); n1=strlen(a); n2=strlen(b); ^ user.cpp:9:21: warning: ignoring return value of ‘char* gets(char*)’, declared with attribute warn_unused_result [-Wunused-result] gets(a); gets(b); n1=strlen(a); n2=strlen(b); ^ /tmp/ccqqZaPD.o: In function `main': user.cpp:(.text.startup+0x53): warning: the `gets' function is dangerous and should not be used.