求学霸教学do while的用法

用do while的方式求3+9+27+...3∧n次方怎么写求学霸帮忙

int i=0, n=5, sum=0, p=1;
do {
p *= 3;
sum += p;
} while( i<=n);

帮助题主编写了一番，完整代码和效果如下：还请采纳！

public class Test {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        System.out.println("请输入3的n次幂的n值：");
        int n = sc.nextInt();
        int i = 0, p = 1, sum = 0;
        do {
            p *= 3;
            i++;
            if (i < n) {

                System.out.print(p + "+");
            } else {
                System.out.print(p + "=");
            }
            sum += p;
        } while (i < n);
        System.out.print(sum);
    }
}