大伙看看这个用eclipse这么做，用for结构还是用什么

``` ```

两个for循环解决，一个for循环打印正三角形，一个for循环打印倒三角形

public class Main {
    public static void main(String[] args) {
        for(int i = 0; i < 4; i++){
            for(int j = 3 - i; j > 0; j--){
                System.out.print(" ");
            }
            System.out.print("*");
            for(int j = 0; j < (i - 1) * 2 + 1; j++){
                System.out.print(" ");
            }
            if(i != 0) System.out.print("*");
            System.out.println();
        }
        for(int i = 0; i < 3; i++){
            for(int j = 0; j <= i; j++){
                System.out.print(" ");
            }
            System.out.print("*");
            for(int j = 0; j < 3 - i * 2; j++){
                System.out.print(" ");
            }
            if(i < 2) System.out.print("*");
            System.out.println();
        }
    }
}

    public static void main(String[] args) {
        int space = 1;
        boolean flag = true;
        System.out.println("   *");
        for (int i=1;i<6;i++){
            for(int j=0;j<(7-space-2)/2;++j){
                System.out.print(" ");
            }
            System.out.print("*");
            for(int k = 0;k < space; ++k){
                System.out.print(" ");
            }
            System.out.print("*");
            System.out.print("\n");
            if(space >=5 ){
                flag = false;
            }
            if(flag){
                space += 2;
            }
            else{
                space -= 2;
            }
        }
        System.out.println("   *");
    }