java math

计数器 （江苏教育考试院）

http://202.102.112.54/statApp/CountApp

 

SimpleCount.java

 

package com.javaeye.lindows.test;

public class SimpleCount {

	/**
	 * @param args
	 */
	private static final int n1 = 2, n2 = 3;

	public void Method(int x, int y) {
		System.out.println(x + y);
		System.out.println(x - y);
		System.out.println((double) x / y);
		System.out.println(x * y);
	}

	public static void main(String[] args) {
		SimpleCount sCount = new SimpleCount();
		sCount.Method(n1, n2);
	}

}

 

 

ForTest.java

 

 

package com.javaeye.lindows.util;

import java.util.Scanner;

/**
 * @author Lindows
 * @see http://www.java2000.net/p11512
 *      http://www.diybl.com/course/3_program/java/javashl/200857/114863.html
 *      http://topic.csdn.net/u/20071017/21/107d54c0-a850-4f0e-b92a-c01c8ba97000.html?seed=2058733001
 */
public class ForTest {

	public ForTest() {

	}
	// 题目：打印1-100的和
	public void forSum() {
		int sum = 0;
		for (int i = 0; i <= 100; i++) {
			sum += i;// sum = sum + i;
		}
		System.out.println("for 循环:" + sum);
		// ---------------------------
		int count2 = 0;
		int sum2 = 0;
		while (count2 <= 100) {
			sum2 += count2;
			// System.out.println(count2);
			count2++;
			// System.out.println(sum2);
		}
		System.out.println("while 循环:" + sum2);
		// ---------------------------
		int count3 = 0;
		int sum3 = 0;
		do {
			sum3 += count3;
			// System.out.println(count3);
			count3++;
			// System.out.println(sum3);
		} while (count3 <= 100);
		System.out.println("do...while 循环:" + sum3);
	}
	// 题目：打印用数组求1-100的和
	public void forArray() {
		// Integer[] intArray = new Integer[100];
		// Integer intArray[] = new Integer[100]; //不建议使用此方式
		int[] intArray = null;
		intArray = new int[100];
		int sum4 = 0;
		for (int i = 0; i < 100; i++) {
			intArray[i] = i + 1;
		}
		for (int j = 0; j < 100; j++) {
			sum4 += intArray[j];
		}
		System.out.println("int或Integer数组循环：" + sum4);
	}
	// 题目：打印1到100中的偶数，一行5个,并求和
	public void forEven() {

		int sum5 = 0;
		for (int i = 1; i <= 100; i++) {
			if ((i % 2 == 0)) {
				System.out.printf("%9d", i);// 或%3d等
				sum5 += i;
				if (i % 5 == 0) {
					System.out.println();
				}
			}
		}
		System.out.println("1到100中的偶数和" + sum5);
	}
	// 题目：打印1到100的各奇偶之和,及奇+偶的和
	public void forInt() {
		int sumOdd = 0; // 设定奇数和的变量
		int sumEven = 0;// 设定偶数之和的变量
		for (int i = 1; i <= 100; i++) {
			while (i % 2 != 0) {
				sumOdd += i;
				break;
			}
			do {
				if (i % 2 == 0) {
					sumEven += i;
				}
				break;
			} while (i > 100);
		}
		System.out.println("1到100中的奇数之和为" + sumOdd);
		System.out.println("1到100中的偶数之和为" + sumEven);
		System.out.println("1到100中的整数之和为" + (sumOdd + sumEven));
	}
	// 题目：打印几何形如：正直角,倒直角,等腰三角,九九乘法表,倒九九表
	public void forGeometric() {
		// 打印：直角三角形
		for (int i = 0; i < 9; i++) {
			for (int j = 0; j < i; j++) {
				System.out.print("*+");
			}
			System.out.println("*");
		}
		System.out.println("---------------------------------");

		// 打印：倒直角三角形
		for (int i = 9; i >= 0; i--) {
			for (int j = i; j >= 0; j--) {
				System.out.print("*-");
			}
			System.out.println("");// 换行
		}
		System.out.println("---------------------------------");
		// 打印：等腰三角形
		final int line = 9;
		for (int i = 0; i < line; i++) {
			for (int j = -(line - 1); j <= i; j++) {
				System.out.print(Math.abs(j) <= i ? "*" : " ");
			}
			System.out.println();
		}
		System.out.println("---------------------------------");
		// 打印：九九乘法表
		for (int m = 1; m <= 9; m++) {
			// System.out.print(m);
			for (int n = 1; n <= m; n++) {
				// System.out.print(n);
				System.out.print(m + "*" + n + "=" + m * n + " ");
			}
			System.out.println(" ");
		}
		System.out.println("---------------------------------");
		// 打印：倒九九乘法表
		for (int x = 9; x >= 1; x--) {
			for (int y = x; y >= 1; y--) {
				System.out.print(x + "*" + y + "=" + x * y + " ");
			}
			System.out.println("");
		}
	}
	// 题目：求4位数的任意3位的排列组合数>>>场景：输入验证码时可能用到
	public void forCombination() {
		// 题目：有1、2、3、4个数字，能组成多少个互不相同且无重复数字的三位数？都是多少？
		// 计数器变量
		int count = 0;
		// 利用三重循环组合数字的百、十、个位
		for (int i = 1; i <= 4; i++) { // 生成百位
			for (int j = 1; j <= 4; j++) { // 生成十位
				for (int k = 1; k <= 4; k++) { // 生成个位
					// 确保i、j、k三位互不相同
					if (i != j && j != k && i != k) {
						++count;// 计数器累加
						// 控制台输出当前组合出的三位数
						System.out.println("第" + count + "种组合：" + i + "" + j
								+ "" + k);
					}
				}
			}
		}
		System.out.println("共计" + count + "种三位数组合方式。");
	}
	// 题目：打印菱形
	public void forDiamond() {
		Scanner input = new Scanner(System.in);
		// 循环标识
		boolean con = true;
		// 菱形的层数和转换计算方式后的层数
		int border, num = 0;
		do {
			con = false;
			System.out.print("请输入要打印的菱形层数[不小于3的奇(整)数]：");
			// 菱形的层数
			border = input.nextInt();
			if (border % 2 == 0 || border < 3) {
				System.out.println("只能输入不小于3的奇(整)数！请重试！");
				con = true;
			}
		} while (con);
		// 转换层数计算方式
		num = border - (border - (border % 2)) / 2;
		// 控制台输出提示
		System.out.println(border + "层菱形图案如下： ");
		// 打印上半部分图象
		for (int i = 1; i <= num; i++) {
			for (int j = 1; j <= num - i; j++) {
				// System.out.print(" "); //这样瘦长一点
				System.out.print("  ");
			}
			for (int j = 1; j <= 2 * (i + 1) - 3; j++) {
				// System.out.print("*"); //这样瘦长一点
				System.out.print("* ");
			}
			System.out.println();
		}
		// 打印下半部分图象
		for (int i = 1; i <= num - 1; i++) {
			for (int j = 1; j <= i; j++) {
				// System.out.print(" "); //这样瘦长一点
				System.out.print("  ");
			}
			int k = num - 1 - i;
			for (int j = 1; j <= 2 * k + 1; j++) {
				// System.out.print("*"); //这样瘦长一点
				System.out.print("* ");
			}
			System.out.println();
		}
	}

	public static void main(String[] args) {
		ForTest fTest = new ForTest();
		// 题目：打印1-100的和
		fTest.forSum();
		System.out.println("---------------------------------");
		// 题目：打印用数组求1-100的和
		fTest.forArray();
		System.out.println("---------------------------------");
		// 题目：打印1到100中的偶数，一行5个,并求和
		fTest.forEven();
		System.out.println("---------------------------------");
		// 题目：打印1到100的各奇偶之和,及奇+偶的和
		fTest.forInt();
		System.out.println("---------------------------------");
		// 题目：打印几何形如：正直角,倒直角,等腰三角,九九乘法表,倒九九表
		fTest.forGeometric();
		System.out.println("---------------------------------");
		// 题目：求4位数的任意3位的排列组合数>>>场景：输入验证码时可能用到
		fTest.forCombination();
		System.out.println("---------------------------------");
		// 题目：打印菱形
		fTest.forDiamond();
		System.out.println("---------------------------------");
	}
}

 

 

SwitchTest.java

 

 

package com.javaeye.lindows.test;

/**
 * 
 * @author lindows
 * @see 题目： 给出一值X，用switcht case语句判断其值(注意,不是用if,else):X<1,X=1,2,3,4,X>4
 *      本题考查了switch的嵌套和三元运算符
 */
public class SwitchTest {

	public void switchMethod1(int x) {
		switch (x) {
		case 1:
			System.out.println("x=1");
			break;
		case 2:
			System.out.println("x=2");
			break;
		case 3:
			System.out.println("x=3");
			break;
		case 4:
			System.out.println("x=4");
			break;
		default:
			// 如果x>4运行x=5,
			switch (x > 4 ? x = 5 : x) {
			case 5:
				System.out.println("x>4");
				break;
			default:
				System.out.println("x<1");
				break;
			}

		}
	}
 
	public String switchMethod2(int y) {
		switch (y) {
		case 1:
			return "y=1";
		case 2:
			return "y=2";
		case 3:
			return "y=3";
		case 4:
			return "y=4";
		default:
			return y > 4 ? "y>4" : "y<1";
		}
	}

	public static void main(String[] args) {
		SwitchTest sTest = new SwitchTest();
		// 输入数字测试
		sTest.switchMethod1(-1);
		sTest.switchMethod1(1);
		sTest.switchMethod1(2);
		sTest.switchMethod1(3);
		sTest.switchMethod1(4);
		sTest.switchMethod1(5);
		System.out.println("--------------------");
		// 输入数字测试
		System.out.println(sTest.switchMethod2(1));
		System.out.println(sTest.switchMethod2(2)); 
		System.out.println(sTest.switchMethod2(3));
		System.out.println(sTest.switchMethod2(4));
		System.out.println(sTest.switchMethod2(5));
		System.out.println(sTest.switchMethod2(0));
	}
}

 

 

end