foo.cc: In function 'int main()':
foo.cc:8:13: error: lvalue required as left operand of assignment
    8 |         if(a%b=0)
      |            ~^~
foo.cc:11:20: warning: suggest parentheses around assignment used as truth value [-Wparentheses]
   11 |             while(c=0)
      |                   ~^~
foo.cc:17:33: error: expected ';' before 'int'
   17 |         printf("最大公约数%d",b)
      |                                 ^
      |                                 ;
   18 |   int n=a<b?a:b;
      |   ~~~                            
foo.cc:19:15: error: 'n' was not declared in this scope
   19 |         while(n)
      |               ^

[Hydro](https://hydro.ac)提供评测服务