![R语言 > pairs(iris[,1:4]) > pairs(iris[1:4]) 这俩语句画的图一样，，那个逗号是干嘛的？？](/aiimages/R%E8%AF%AD%E8%A8%80+%26amp%3Bgt%3B+pairs%28iris%5B%2C1%3A4%5D%29+%26amp%3Bgt%3B+pairs%28iris%5B1%3A4%5D%29+%E8%BF%99%E4%BF%A9%E8%AF%AD%E5%8F%A5%E7%94%BB%E7%9A%84%E5%9B%BE%E4%B8%80%E6%A0%B7%EF%BC%8C%EF%BC%8C%E9%82%A3%E4%B8%AA%E9%80%97%E5%8F%B7%E6%98%AF%E5%B9%B2%E5%98%9B%E7%9A%84%EF%BC%9F%EF%BC%9F.png)
public class Utils {
public static double add(double num1, double num2) {
return num1 + num2
}
public static double substract(double num1, double num2) {
return num1 - num2
}
public static double mulitply(double num1, double num2) {
return num1 * num2
}
public static double division(double num1, double num2) {
if (num2 == 0) {
return -1
}
return num1 / num2
}
}package cn.campsg.java.experiment
import java.util.Scanner
public class MainClass {
public static void main(String[] args) throws Exception {
double[] nums
double num1
double num2
double result
Scanner scanner = new Scanner(System.in)
System.out.println("请输入用于计算的两个数值，数值间用空格分隔")
System.out.println("请输入加e5a48de588b662616964757a686964616f31333365653864数与被加数:")
nums = trans(scanner.nextLine())
num1 = nums[0]
num2 = nums[1]
result = Utils.add(num1, num2)
print("和为：", result)
System.out.println("请输入减数与被减数:")
nums = trans(scanner.nextLine())
num1 = nums[0]
num2 = nums[1]
result = Utils.substract(num1, num2)
print("差为：", result)
System.out.println("请输入乘数与被乘数:")
nums = trans(scanner.nextLine())
num1 = nums[0]
num2 = nums[1]
result = Utils.mulitply(num1, num2)
print("积为：", result)
System.out.println("请输入除数与被除数:")
nums = trans(scanner.nextLine())
num1 = nums[0]
num2 = nums[1]
result = Utils.division(num1, num2)
if (result == -1) {
System.out.println("分母不能为0")
} else {
print("商为：", result)
}
}
/**
* 把输入内容转换成两个数字
*
* @param input 输入的字符传
* @return 数值型数值
* @throws Exception
*/
public static double[] trans(String input) throws Exception {
try {
String[] arr = input.split(" ")
return new double[]{Double.parseDouble(arr[0]), Double.parseDouble(arr[1])}
} catch (Exception e) {
throw new Exception("输入格式错误")
}
}
/**
* 打印结果
*
* @param msg 前缀
* @param num 结果
*/
public static void print(String msg, double num) {
if (num == (int) num) {
System.out.println(msg + (int) num)
} else {
System.out.println(msg + num)
}
}
}
上面是代码，工程自己创建把代码复制进去就可以了。
首先可以把计算器看成是一个对象就是一个类,它有加、减、乘、除功能，这四个就是这个类的方法你可以给这个类定义两个成员变量int
x、int
y
然后分别用这四个方法对x
、y
实行加、减、乘、除并返回其值
代码大概如下：
class
counter{
private
int
x
private
int
y
public
counter(){
}
public
counter(int
x,int
y){
this.x=x
this.y=y
}
public
double
adding(){
//加运算
return
x+y
}
public
double
minus(){
//减运算
return
x-y
}
public
double
times(){
//乘运算
return
x*y
}
public
double
divide(){
//除运算
return
x/y
}
}
//测试类
public
class
test{
public
static
void
main(string[]
args){
counter
c=new
counter(5,4)//实例化
system.out.println(c.adding())//输出加的结果
system.out.println(c.minus())//输出减的结果
system.out.println(c.times())//输出乘的结果
system.out.println(c.divide())//输出除的结果
}
}
希望对你有帮助
