/in/foo.cc: In function 'bool isZhiShu(int)':
/in/foo.cc:7:21: error: expected primary-expression before '||' token
    return(a%2!=0&&a%||a==2);
                     ^~
/in/foo.cc:9:18: warning: suggest parentheses around assignment used as truth value [-Wparentheses]
  for(int i=0;i=a-1;i++){
                  ^