程序的目的是实现：a+aa+aaa+... ...+aaa..aaa(n个a)的和，如n=3，a=2,则为：2+22+222。我的代码如下：
#include <math.h>
main ()
{
    long int a, temp=0, add=0, sum=0;
    int n, i;
    printf("Please input positive integers 'a' and 'n':\n");
    scanf("%ld %d", &a, &n);
    while (a<=0 || n<=0)
    {
        printf("Sorry! 'a' or 'n' doesn't fit. Please input 'a' & 'n' again:\n");
        scanf("%ld %d", &a, &n);
    }
    while (a>=10)
    {
        printf("Sorry! 'a' can not be larger than 9. Please input 'a' & 'n' again:\n");
        scanf("%ld %d", &a, &n);
    }
    for (i=n; i>0; i--)
    {
        temp=temp+a*pow(10,i-1);
    }
    add=(int)(temp);
    sum=add;
    while (add>9)
    {
        add=(int)(add/10);
        sum=sum+add;
    }
    printf("%d+%d%d+...+%d=%d.\n",a,a,a,(int)(temp),sum);
}
编译通过，测试：a=2, n=6，结果完全不对，a甚至还等于0了。我郁闷了，到底错哪了？怎么也调不出来！谢谢了！

那该如何解决呢？