C语言，太头疼了，好难受啊～

#include<stdio.h>

int main()
{
    int a,n,i,temp;
    printf("Enter a,n:");
    scanf("%d %d", &a, &n);
    temp = a;
    double s=0;
    for ( i=1; i<=n; i++ ) {
        s += a;
        a = a*10+temp;
    }
    printf("s = %.0lf",s);
    
    return 0;
}

#include<stdio.h>
int main(){
    int a,n;
    scanf("%d%d",&a,&n);
    int sum = 0;
    int s = 0;
    int i,j;
    for( i = 1 ; i <= n;i++){
        j = i;
        while(j>0){
            s *= 10;
            s += a;
            j--;  
        }
        sum += s;
        s = 0;
    }
    printf("%d",sum);
        return 0;
}

#include<stdio.h>
 int main(void)
 {
     int s=0,q=2,i,n;
     scanf("%d",&n);
     for(i=0;i<n;i++)
     {
         s=s+q;
         q=q*10+2;}
         printf("%d",s);
         
         return 0;}