c语言DO While 输入变量同样变量，结果不一样，请大佬帮忙找下原因？

Question

# include <stdio.h>int main (void){ int i, val; int sum = 0; do { printf ("请输入一个整数判断是否是回文数\n"); scanf ("%d",&val); { i = val; while (i) { sum = sum * 10 + i % 10; i /= 10; } if (sum == val) printf ("是"); else printf ("不是"); } } while (1); return 0 ;}

Answer 1

i = val;
sum = 0;
如上，在i句下添一句。sum需要重新初始化