【java】练习

public class Demo5 {
    public static void main(String[] args) {
        // 0-100之间奇数odd和偶数even的和
        int oddSum = 0;
        int evenSum = 0;

        for (int i = 0; i <= 100; i++) {
            if (0 == i % 2) {
                evenSum += i;
            } else {
                oddSum += i;
            }
        }
        System.out.println("偶数之和是：" + evenSum + "\n奇数之和是：" + oddSum);
    }
}

public class Demo6 {
    public static void main(String[] args) {
        int count = 0;
        //1-100之间能被5整数的数，并且每行输出3个
        for (int i = 0; i <= 100; i++) {
            if (0 == i % 5) {
                System.out.print(i+" ");
                count++;
                if(3<=count){
                    count = 0;
                    System.out.println();
                }
            }
        }
    }
}

/**
 * @author 
 * @date 
 * 文件描述：九九乘法表
 */
public class Demo7 {
    public static void main(String[] args) {
        for (int j = 1; j <= 9; j++) {
            for (int i = 1; i < j + 1; i++) {
                System.out.print(i + "x" + j + "=" + i * j + "\t");
            }
            System.out.println();
        }
    }
}

/**
 * 文件描述：打印5行三角形
 */

public class Demo8 {
    public static void main(String[] args) {
        for (int i = 1; i <=5; i++) {
            for (int m=5;m>i;m--){
                System.out.print(" ");
            }
            for (int j = 1; j <=i; j++) {
                System.out.print("*");
            }
            for (int n = 1; n <i; n++) {
                System.out.print("*");
            }
            System.out.println();
        }
    }
}