Compilare: main.cpp: In function 'int main()': main.cpp:28:24: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for ( int j = 0; j < strlen( s[i] ); ++j ) { ~~^~~~~~~~~~~~~~~~ main.cpp:32:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for ( int j = 0; j < strlen( s[i] ); ++j ) { ~~^~~~~~~~~~~~~~~~