C语言问题

#include <stdio.h>
int main(void)
{
int i;
int sum = 0,j = 0,m;
m = sum/j;
/* 为什么把m的定义放于此处，运行结果会是程序出错 */
for (i=1; i<=100; ++i)
{
if(i%2 == 1)
{
sum = sum + i;
j++;
}
}
printf("m = %d\n", m);
return 0;
}