View Compilation Error

0_0_39218862_30968.cpp: In function 'int main()':
0_0_39218862_30968.cpp:18:32: error: 'm' was not declared in this scope
   18 |                 printf("%d\n", m / 2);//一个汉字占两个字节a【i】和a【i+1】都是一个字
      |                                ^