第四次上机

package hyy;

public class case1 {
private float a; //上个月电表读数
private float b; //本月电表读数
public case1(){

}
public case1(float a,float b){
this.a=a;
this.b=b;
}

public void getdata(){
System.out.println("上个月的电表读数为："+a+"\n本月的电表读数为："+b);
}

public void setdata(){
if(b==1450){
b=1500;
}
float c=1.2f;
float d; //本月用电量
float sum; //本月所用电费
d=b-a;
sum=d*c;
System.out.println("本月所用电费为："+sum);

}
public static void main(String[] args){
case1 s1=new case1();
s1.a=1000;
s1.b=1200;
s1.setdata();
s1.getdata();
case1 s2=new case1(1200,1450);
s2.setdata();
s2.getdata();
}
}

package hyy;

public class cylinder1 {
private int r;                  //圆柱体的底面半径
private int h;                  //圆柱体的高
final float p=3.14f;

public cylinder1(int r,int h){
    this.r=r; 
    this.h=h;
}

public float area(){          //计算底面积
    float s;
    s=p*r*r;
    return s;
}

public float volume(){             //计算圆柱体积
    float v;
    v=area()*h;
    return v;
}

public void printlndata(){
    System.out.println("圆柱底面的半径为："+r+"\n圆柱的高为："+h+"\n圆柱的底面积为："+area()+"\n圆柱的体积为："+volume());
}

public static void main(String[] args){
    cylinder1 s1=new cylinder1(5,9);
    s1.printlndata();
    cylinder1 s2=new cylinder1(2,7);
    s2.printlndata(); 
}
}

package hyy;

import java.util.*;
public class operation {
private int a;
private int b;
private String c1;
private char c2;

public void addition(){
    int sum=a+b;
    System.out.println("两个数相加的和为："+sum);  
}

public void minus(){
    int s;
    s=a-b;
    System.out.println("两个数相减的差为："+s);    
}

public void multiply(){
    int m;
    m=a*b;
    System.out.println("两个数相乘的积为："+m);       
}

public void division(){
    float d;
    if(b==0){
        System.out.println("b的值不能为0！");   
    }
    d=a/b;
    System.out.println("两个数相除的商为："+d);    
    }

public static void main(String[] args){
    operation s1=new operation();
    //count s2=new count();
    @SuppressWarnings("resource")
    Scanner operation=new  Scanner(System.in);
    System.out.println("请输入两个需要计算的数：");  
    s1.a=operation.nextInt();
    s1.b=operation.nextInt();
    System.out.println("请输入相应的运算符：");
    s1.c1=operation.next();
    s1.c2=s1.c1.charAt(0);
    if(s1.c2==‘+‘){
        s1.addition();
    }
    else if(s1.c2==‘-‘){
        s1.minus();
    }
    else if(s1.c2==‘*‘){
        s1.multiply();
    }
    else if(s1.c2==‘/‘){
        s1.division();
    }
    else System.out.println("错误！");
}
}