/in/foo.cc: In function 'int main()':
/in/foo.cc:8:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int i=0;i<s.size();i++)
              ~^~~~~~~~~
/in/foo.cc:9:30: warning: suggest parentheses around '&&' within '||' [-Wparentheses]
   if(isdigit(s[i])||s[i]>='A'&&s[i]<='Z'||s[i]>='a'&&s[i]<='z')ans++;
                               
/in/foo.cc:9:52: warning: suggest parentheses around '&&' within '||' [-Wparentheses]
   if(isdigit(s[i])||s[i]>='A'&&s[i]<='Z'||s[i]>='a'&&s[i]<='z')ans++;