Compilare: user.cpp: In function ‘int main()’: user.cpp:14:29: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=1;i<=strlen(a)-2;i++) ^ user.cpp:24:38: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] j+=2;}while(j<=strlen(a)-2 && k==0); ^ user.cpp:39:29: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(i=1;i<=strlen(a)-1;i++) ^ user.cpp:46:34: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(j=i;j<=strlen(a)-1;j++) ^