foo.cc: In function 'int main()':
foo.cc:7:14: error: expected primary-expression before ';' token
     string s[;
              ^
foo.cc:7:14: error: expected ']' before ';' token
foo.cc:10:9: error: 's' was not declared in this scope
         s+=c;
         ^
foo.cc:14:17: warning: suggest parentheses around '&&' within '||' [-Wparentheses]
         if(a>=11&&a-b>=2||b>=11&&b-a>=2) {cout<<a<<':'<<b<<endl;a=0;b=0;}
            ~~~~~^~~~~~~~
foo.cc:17:16: error: 's' was not declared in this scope
     for(auto x:s)
                ^
foo.cc:22:17: warning: suggest parentheses around '&&' within '||' [-Wparentheses]
         if(a>=21&&a-b>=2||b>=21&&b-a>=2) {cout<<a<<':'<<b<<endl;a=0;b=0;}
            ~~~~~^~~~~~~~