Compilare: user.cpp: In function ‘bool litera(char)’: user.cpp:12:20: warning: suggest parentheses around ‘&&’ within ‘||’ [-Wparentheses] return (c>='a')&&(c<='z')||(c>='A')&&(c<='Z'); ^ user.cpp: In function ‘void text(std::string, int&, int&)’: user.cpp:16:28: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i=0; i<s.size(); i++) ^ user.cpp: At global scope: user.cpp:22:6: warning: ISO C++ forbids declaration of ‘main’ with no type [-Wreturn-type] main() ^