C语言练习题，求s = a+aa+aaa+... ...+aaa...a的值，其中a是一个数字，如2+22+222+2222,a的值和加数个数n，均从键盘获取。要求a属于[1,9]，n小于10

实验4-2（do...while循环）：
求s = a+aa+aaa+... ...+aaa...a的值，其中a是一个数字，如2+22+222+2222,a的值和加数个数n，均从键盘获取。要求a属于[1,9]，n小于10（如果不满足此条件，就重输入）。
输入：输入a值和n值
输入提示信息："Please input a :"
输入格式："%d"
输入提示信息："请输入n:"
输入格式："%d"
如：
请输入a:8
请输入n:9
输出：算式及和
输出提示信息：
"Sum=算式“，输出格式”%ld“ 
”Sum=和，输出格式”%ld“
如：
Sum=8+88+888+8888+88888+888888+88888888+888888888 
Sum=987654312重点题！！！！！！

Find the value of s= a + aa + aaa +... + aaa... a, where a is a number, such as 2 + 22 + 222 + 2222. The value of a and the number of addends n are obtained from the keyboard. It is required that a belongs to [1,9] and N is less than 10 (if this condition is not met, re-enter).
Input: enter a value and n value
Enter the prompt: "please input a:"
Input format: '% d'
Enter the prompt: "please input n:"
Input format: '% d'
For example:
Please input a:8
Please input n:9
Output: formula and sum
Output prompt:
"Sum = expression", output format "% LD"“
”Sum = sum, output format "% LD"“
For example:
Sum=8+88+888+8888+88888+888888+8888888+88888888+888888888
Sum=987654312

代码如下：

#include <stdio.h>int main()
{	    	 		 	   long  a = 0;long  b = 0;int n = 0;int i;long sum = 0;do{	    	 		 	   printf("Please input a:");scanf("%d", &a);//1printf("Please input n:");scanf("%d", &n);//1}while (a > 9 || a < 0 || n > 11 || n < 0);//2printf ("Sum=");for (i = 0; i < n; i++){	    	 		 	   b = a + b;//1if (i == 0){	    	 		 	   printf ("%ld", b);}else{	    	 		 	   printf ("+%ld", b);}sum += b;//2a = 10 * a;//2}printf ("\nSum=%ld\n", sum);
}