练习

//打印三角形 5行

for (int i = 1; i <= 5; i++) {
    for (int j = 5; j >=i ; j--) {
        System.out.print(" ");
    }
    for (int j = 1; j <=i ; j++) {
        System.out.print("*");
    }
    for (int j = 1; j < i; j++) {
        System.out.print("*");
    }
    
    System.out.println();
}

    *
   ***
  *****
 *******
*********

【【狂神说Java】Java零基础学习视频通俗易懂】https://www.bilibili.com/video/BV12J41137hu?p=33&vd_source=fd5defd6aaa826e3b6e0c06073353e32