#include<stdio.h>
main()
{
    int a,i,j;
    char f = 'y';
    do
    {   
        printf("\n enter a number:");
        scanf("%d",&a);   
        if (a>20)
        {
                printf("\n please enter a <20 num!\n");
                printf("\nenter 'y' begin! enter'n' stop!");
                goto AAA;               
        }                    
        else
        {
                for (i=1;i<=a;i++)
                {
                                for (j=i;j<=a;j++)
                                printf("*");
                                printf("\n");
                }                           
        }
        AAA:
            {
                        printf("\nenter (y/n) continue!");
                        f = getchar();
            }               
            
    }while (f=='y' || f=='Y');
}


我是一个菜菜鸟,请问如何能让它Loop呢?

我要撤消这个问题