/in/foo.cc: In function 'int main()':
/in/foo.cc:13:8: warning: suggest parentheses around assignment used as truth value [-Wparentheses]
   13 |    if(a='+'){
      |       ~^~~~
/in/foo.cc:18:14: warning: suggest parentheses around assignment used as truth value [-Wparentheses]
   18 |    }else if(a='-'){
      |             ~^~~~