fzx的2-6

#include <stdio.h>
#include <math.h>

int fun(int);
int main(void)
{
    int a, n, result;
    scanf("%d%d", &a, &n);
    result = a * fun(n);
    for (int i = n - 1; i > 0; i--)
    {
        result -= a *fun(i);
    }
    printf("%d",result);
}

int fun(int n)
{
    int sum = 0;
    for (int i = 0; i < n; i++)
    {
        sum += pow(10, i);
    }
    return sum;
}