#define _CRT_SECURE_NO_WARNINGS
#include <stdio.h>
#include <stdlib.h>
int main()//求Sa = a + aa + aaa +aaaa + aaaaa(前五项之和)
//aa = a + 10*a a...a(m个) = 10*(m - 1) + a
{
int i, n, m;//n为数字a，m为要加多少项
int sum = 0;
int tmp = 0;
printf("请输入数字：");
scanf("%d%d", &n, &m);
for (i = 1; i <= m; i++){
tmp = tmp * 10 + n;
sum += tmp;
}
printf("sum = %d\n", sum);
system("pause");
return 0;
}