求Sn的和如2+22+222+2222

int main(void){
int a=0,n=0;
printf("input a and n:");
scanf("%d %d",&a,&n);
long sum=0;
int temp=a;
int j=n;
for(int i=1;i<=n;i++){

    for(j=i;j>1;j--){
    temp=a+temp*10;
    }
    sum+=temp;
    temp=0;
}

printf("the sum is %ld\n",sum);

}