/in/foo.cc: In function 'int main()':
/in/foo.cc:24:12: warning: suggest parentheses around assignment used as truth value [-Wparentheses]
    if(add=x){
            ^
/in/foo.cc:14:4: warning: 'c' may be used uninitialized in this function [-Wmaybe-uninitialized]
   c+=s2;
   ~^~~~
/in/foo.cc:13:4: warning: 'b' may be used uninitialized in this function [-Wmaybe-uninitialized]
   b+=s1;
   ~^~~~