java经典编程题二及详细答案

System.out.println(\该成绩为优\ } else if (grade >= 80 && grade < 90) { System.out.println(\该成绩为良\ } else if (grade >= 70 && grade < 80) { System.out.println(\该成绩为中\ } else if (grade >= 60 && grade < 70) { System.out.println(\该成绩及格\ } else {

System.out.println(\该成绩不及格\ } }

}结果截图：

? 提高题

1） 程序如下：

import java.util.Scanner; public class fangcheng {

public static void main(String[] args) {

Scanner input = new Scanner(System.in); System.out.println(\请输入a\ double a=input.nextDouble(); System.out.println(\请输入b\ double b=input.nextDouble(); System.out.println(\请输入c\ double c=input.nextDouble(); if(a==0)

{ System.out.println(\对不起该方程不是一元二次方程\ else if(b*b-4*a*c==0)

{System.out.println((-b Math.sqrt(b*b-4*a*c))/(2*a)); } else if (b*b-4*a*c>0) {

System.out.println(\第一个答案为\ System.out.println(\第二个答案为\ } else

{System.out.println(\对不起没有答案\ } }

截图如下：

2） 程序如下：

import java.util.Scanner; public class Tax {

public static void main(String[] args) { double s;

Scanner input = new Scanner(System.in); System.out.println(\请输入所得税额t\ double t=input.nextDouble();; if(t==500)

{System.out.println(\应纳个人所得税税额为:25\ else if(t<=2000) { s=0.1*t-25;

System.out.println(\应纳个人所得税税额为:\ else if (t<=5000) { s=0.15*t-125;

System.out.println(\应纳个人所得税税额为:\

else if (t<=20000) { s=0.2*t-375;

System.out.println(\应纳个人所得税税额为:\ else if (t<=40000) { s=0.25*t-1375;

System.out.println(\应纳个人所得税税额为:\ else if (t<=60000) { s=0.3*t-3375;

System.out.println(\应纳个人所得税税额为:\ else if (t<=80000) { s=0.35*t-6375;

System.out.println(\应纳个人所得税税额为:\ else if (t<=100000) { s=0.4*t-10375;

System.out.println(\应纳个人所得税税额为:\ else

{ s=0.45*t-15375;

System.out.println(\应纳个人所得税税额为:\ } }

结果截图：

实验2.3

? 基本题

1）程序如下： import java.io.*; public class Sanjiao {

public static void main(String[] args) {

int n=0; try {

BufferedReader in = new BufferedReader(new InputStreamReader(System.in));

System.out.println(\请输入一个整数:\ String r = in.readLine(); n = Integer.parseInt(r); }

catch(Exception E){}

System.out.print(\相应三角形如下:\ for(int i=0;i<=n;i ) {

for(int j=0;j

结果截图：

2）程序如下： public class sum {

public static void main(String[] args) { float sum = 0F;

for(int i = 1; i <=100; i ){ if(i % 2 == 0){ sum -= (float)1 / i;