Compilare: user.cpp: In function ‘int main(int, const char**)’: user.cpp:38:41: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for( int i = 30; i < str.length(); i ++ ) { ^ user.cpp:80:55: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for( int j = 0; j + w[i] < str.length(); j += v[i] ) { ^ user.cpp:82:44: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for( int i = 1; i < str.length(); i ++ ) { ^