Compilare: user.cpp: In function ‘int txt(std::string)’: user.cpp:13:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i=0;i<s.size();i++) ^ user.cpp:15:22: warning: suggest parentheses around ‘&&’ within ‘||’ [-Wparentheses] if (s[i]>=97 && s[i]<=122 || s[i]>=65 && s[i]<=90) ^ user.cpp:18:54: warning: suggest parentheses around ‘&&’ within ‘||’ [-Wparentheses] if (s[i+1]<65 || s[i+1]>122 || s[i+1]>90 && s[i+1]<97 ) ^ user.cpp:10:13: warning: unused variable ‘c’ [-Wunused-variable] int n=0,c=0,k=0; ^ user.cpp: At global scope: user.cpp:27:6: warning: ISO C++ forbids declaration of ‘main’ with no type [-Wreturn-type] main() ^