for循环

表达式

package com.struct;

//for
public class ForDemo {
    public static void main(String[] args) {
                                                                 //计算1-100的奇数和，偶数和
        int evensum = 0;
        int oddsum = 0;
        //for(初始，条件判断，迭代){}
        for (int i = 0; i <= 100; i++) {
            if (i % 2 == 0) {
                evensum = evensum + i;
            } else {
                oddsum = oddsum + i;
            }

        }
        System.out.println("偶数和" + evensum);
        System.out.println("基数和" + oddsum);


                                                     //用while或for循环输出1-1000之间能被5整除的数，并且每行输出3个
                                            // printLn输出完会换行
                                            // print输出完不会换行

        for (int i = 0; i <= 1000; i++) {
            if (i % 5 == 0) {
                System.out.print(i + "\t");
                if (i % 15 == 0) {
                    System.out.print("\n");
                }
            }

        }

    }
}

乘法口诀

                                                            //99乘法口诀
public class FoeDemo02 {
    public static void main(String[] args) {
        for (int x = 1; x <= 9; x++) {
            for (int y = 1; y <= x; y++) {
                System.out.print(x + "*" + y + "=" + (x * y) + "\t");

            }
            System.out.println();

        }
    }
}