Compilare: user.cpp: In function ‘int main()’: user.cpp:14:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0;i<strlen(s);i++) ^ user.cpp:20:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] {for(i=0;i<strlen(s);i++) ^ user.cpp:34:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0;i<strlen(s);i++) ^ user.cpp:102:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=0;i<strlen(s);i++) ^