Compilare: user.cpp: In function ‘int main()’: user.cpp:19:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0;i<strlen(s);i++) ^ user.cpp:24:29: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while(j<strlen(s)) ^ user.cpp:32:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0;i<strlen(s);i++) ^ user.cpp:49:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0;i<strlen(s);i++) ^