Java (for循环基础应用)

深藏阁楼爱情的钟 2022-09-24 11:27 170阅读 0赞

**①：定义两个变量，并同时计数**

package Z1;
     
    public class Test2 {
       public static void main(String[] args) {
           int sum = 0;
           for (int a = 1, b = 100; a < b; a++, b--) {
           sum += a + b;
            }
          System.out.println(sum);
         }
    }

**②：5乘5矩阵**

public class Test3 {
     
       public static void main(String[] args) {
     
          int i, j, k;
          for (i = 0; i < 5; i++) {
          for (j = 0; j < 5; j++) {
          System.out.print("");
        }
         for (k = 0; k < 5; k++) { 
         System.out.print("*");
         }
        System.out.println(); 
       }
      }

**运行效果：**

**![Center][]**

③：九九乘法表

public class Test4 { 
        public static void main(String[] args) {
           int i, j;
            for (i = 1; i < 10; i++) {
            for (j = 1; j <= i; j++) {
            System.out.print(j + "*" + i + "=" + i * j + "\\t");
         }
            System.out.println();
        }
            for (i = 9; i > 0; i--) {
            for (j = 1; j <= i; j++) {
            System.out.print(j + "*" + i + "=" + i * j + "\\t");
          }
       System.out.println();
      }
     }
    }

**![Center 1][]**

**④：金字塔**

package Z1;
     public class Test5 {
       public static void main(String[] args) {
          int i, j;
          for (i = 1; i <= 9; i++) {
          for (j = 9 - i; j >= 0; j--) {
          System.out.print(" ");                                          // 输出左边的空格
        }
          for (j = 1; j <= 2 * i - 1; j++) {
          System.out.print("*");                                         // 输出金字塔
        }
          System.out.println();
       }
      }
     }

**运行效果**

**![Center 2][]**

[Center]: /images/20220719/7f3a8bbcc42046539cbfdd9f75b073fa.png
[Center 1]: /images/20220719/cf85f34d8e87475fae7c3d614f06bcf6.png
[Center 2]: /images/20220719/a3017cd73b6f496596f313c45683df68.png