软件工程个人作业02

1.设计思想：

在四则运算1的基础上，多加了几个要求，是否有乘除法可以通过不同的选择然随机生成符号的函数有时候生成两个数字对应加减，有时候生成四个数对应加减乘除；括号没有实现；数值范围通过一个函数实现(int)(Math.random()*(m-n+1)+n)生成n~m的数字；加减有无负数在减法出负数时输出提示语句；另外求余，即把参与运算的两个数都定义为int类型，比如a,b都为int，a/b=c,若不能整除，余数等于a-c*b。

2.

package 加减乘除;
import java.util.Random;
import java.util.Scanner;
class jisuan{
static double z = 0;
    public static double rand(){
        double n = 0;
        Random ra =new Random();    
        int a=ra.nextInt(100)+1;
        {System.out.print(a);
        n=a;}
        return n;
    
    }
    public static char fuhao(){
        char n = 0;
        Random ra =new Random();    
        int c=ra.nextInt(100)+1;
        if(c>=0&&c<25){System.out.print("+"); n = '+';}
        if(c<50&&c>=25){System.out.print("-"); n = '-';}
        if(c>=50&&c<75){System.out.print("*"); n = '*';}
        if(c>=75&&c<100){System.out.print("/"); n = '/';}    
        return n;        
    }  
    public static double zhen(){
        double n = 0;
        Random b =new Random();double b1=b.nextInt(10)+1;
        Random c =new Random();double c1=c.nextInt(10)+1;     
        if(b1>=c1||b1==c1){
            zhen();
        }
        else{
        System.out.print(b1+"/");System.out.print(c1);
        n=b1/c1;
        
        }
        
        return n;
    
        
    }
    public static double zhengzhen(){
        double n = 0;
        Random a =new Random();double a1=a.nextInt(10)+1;
        Random b =new Random();double b1=b.nextInt(10)+1;
        Random c =new Random();double c1=c.nextInt(10)+1;     
        if(b1>c1){
            zhengzhen();
        }
        else if(b1==c1){
            System.out.print(a1);
            n=a1;
            }
        else{    
            System.out.print(b1+"/");System.out.print(c1);
            n=b1/c1;
        }
        return n;
    }
    public static void zhengshow(){      
        double a =rand();char c = fuhao();double b = rand();System.out.println("=");
        double n = 0;
        if(c=='+'){
            n= a+b;
        }
        if(c=='-'){
            n= a-b;
        }
        if(c=='*'){
            n= a*b;
        }
        if(c=='/'){
            n= a/b;
        }
        System.out.println(n);
        System.out.println("");
    }
    public static void zhengshowwuchegnchu(){      
        char c = fuhao();
        if(fuhao()!='*'||fuhao()!='/')
        {
        double a =rand();double b = rand();System.out.println("=");
        double n = 0;
        if(c=='+'){
            n= a+b;
        }
        if(c=='-'){
            n= a-b;
        }
        if(c=='*'){
            n= a*b;
        }
        if(c=='/'){
            n= a/b;
        }
        System.out.println(n);
        System.out.println("");
        }
        else{
            zhengshowwuchegnchu();
        }
    }
    public static void zhenshow(){
        
        double a =zhen();char c = fuhao();double b = zhen();System.out.println("=");
        
        double n = 0;
        if(c=='+'){
            n= a+b;
        }
        if(c=='-'){
            n= a-b;
        }
        if(c=='*'){
            n= a*b;
        }
        if(c=='/'){
            n= a/b;
        }
        System.out.println(n);
        System.out.println("");
        
    }
    public static void zhengzhenshow(){
        
        double a =zhengzhen();char c = fuhao();double b = zhengzhen();System.out.println("=");
        double n = 0;
        if(c=='+'){
            n= a+b;
        }
        if(c=='-'){
            n= a-b;
        }
        if(c=='*'){
            n= a*b;
        }
        if(c=='/'){
            n= a*(1/b);
        }
        System.out.println(n);
        System.out.println("");
        
    }

}
public class test {
    public static void main(String[] args){
        Scanner in = new Scanner(System.in);
        System.out.println("请输入显示式子的个数：");
        int m = in.nextInt();
        System.out.println("1.式子只有整数");
        System.out.println("2.式子只有真分数");
        System.out.println("请输入要执行的操作：");
        String[] strArray=new String[m];
         int type = in.nextInt();
        switch(type){
        case 1:{
            System.out.println("是否有乘除法：(1有0没有)");
            int n = in.nextInt();
            if(n==1){
            for(int i = 0;i<m;i++){
            jisuan.zhengshow();    
            }
            }
            if(n==0){
                for(int i = 0;i<m;i++){
                jisuan.zhengshowwuchegnchu();    
            
                }
            
                }
            } break;
        
        case 2:{
            for(int i = 0;i<m;i++){
            jisuan.zhenshow();
            }
            } break;
        
        
        }
    }
    }


    

3.运行结果截图：