java期中测试

Java程序设计期中考试

1. 计算n!=123…*n.(20分)
2. 输入10个整数，然后逆序输出这个10个整数。(20分)
3. 计算S=1-1/(2^2)+1/(3^3)-1/(4^4)+…+(-1)^(n-1)/(n^n) (20分)
4. 设计一个复数类Complex,用来实现加减运算，并在屏幕上输出当前复数。(30分)

第一题：

import java.util.Scanner;

public class test1 {
    public static void main(String[]args){
        int ss;
        System.out.println("请输入一个数:");
        Scanner console=new Scanner(System.in);
        ss=console.nextInt();
        int s=1;
        for(int i=ss;i>=1;i--){
            s=s*i;
        }
        System.out.println(s);
    }
}

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第二题：

import java.util.Scanner;
public class test {
    public static void main(String[]args){
        System.out.println("请输入10个数，以空格隔开:");
        Scanner sc = new Scanner(System.in);
        String str = sc.nextLine().toString();
        String[] arr  = str.split(" ");
        int[]b = new int[arr.length];
        for(int j = 0; j<b.length;j++) 
        {
                b[j] = Integer.parseInt(arr[j]);
        }
        int n=b.length;
        for (int i = 0; i < n; i++) {
            for (int j = 0; j < n - i - 1; j++) {
                if (b[j] > b[j + 1]) {
                    int t=b[j];
                    b[j]=b[j+1];
                    b[j+1]=t;
                }
            }
        }
        for(int k=n-1;k>=0;k--){
            System.out.print(b[k]+" ");
        }
    }
}

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第三题:

import java.util.Scanner;
public class test {
    public static void main(String[]args){
        int n;
        System.out.print("请输入一个数:");
        Scanner console=new Scanner(System.in);
        n=console.nextInt();
        double s=0;
        for(int i=1;i<=n;i++){
            double a=0;
            if(i%2==0){
                a=-1/(Math.pow(i,i));
            }
            else{
                a=1/(Math.pow大专栏  java期中测试="token punctuation">(i,i));
            }
            s=s+a;
        }
        System.out.println(s);
    }
}

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第四题：

import java.util.Scanner;  

public class Complex { 
    double real;  
    double image;

    Complex(){  
        Scanner input = new Scanner(System.in);  
        double real = input.nextDouble();  
        double image = input.nextDouble();  
        Complex(real,image);  
    }  

    private void Complex(double real, double image) { 
        // TODO Auto-generated method stub  
        this.real = real;  
        this.image = image;  
    }  

    Complex(double real,double image){
        this.real = real;  
        this.image = image;  
    }  

    public double getReal() {  
        return real;  
    }  

    public void setReal(double real) {  
        this.real = real;  
    }  

    public double getImage() {  
        return image;  
    }  

    public void setImage(double image) {  
        this.image = image;  
    }  

    Complex add(Complex a){ // 相加  
        double real2 = a.getReal();  
        double image2 = a.getImage();  
        double newReal = real + real2;  
        double newImage = image + image2;  
        Complex result = new Complex(newReal,newImage);  
        return result;  
    }  

    Complex sub(Complex a){ // 相减  
        double real2 = a.getReal();  
        double image2 = a.getImage();  
        double newReal = real - real2;  
        double newImage = image - image2;  
        Complex result = new Complex(newReal,newImage);  
        return result;  
    }  
    public void print(){ // 输出  
        if(image > 0){  
            System.out.println(real + " + " + image + "i");  
        }else if(image < 0){  
            System.out.println(real + "" + image + "i");  
        }else{  
            System.out.println(real);  
        }  
    }  
    public static void main(String[] args) {  

        System.out.println("请用户输入第一个复数的实部和虚部:");  
        Complex data1 = new Complex();  
        System.out.println("请用户输入第二个复数的实部和虚部:");  
        Complex data2 = new Complex();  
        Complex result_add = data1.add(data2);  
        Complex result_sub = data1.sub(data2);   

        result_add.print();  
        result_sub.print();  
    }  
}  

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