我试图创建一个计算器,但我不能让它工作,因为我不知道如何获得用户输入。

如何在Java中获得用户输入?


当前回答

import java.util.Scanner;

public class Myapplication{
     public static void main(String[] args){
         Scanner in = new Scanner(System.in);
         int a;
         System.out.println("enter:");
         a = in.nextInt();
         System.out.println("Number is= " + a);
     }
}

其他回答

在java中输入是非常简单的,你所要做的就是:

import java.util.Scanner;

class GetInputFromUser
{
    public static void main(String args[])
    {
        int a;
        float b;
        String s;

        Scanner in = new Scanner(System.in);

        System.out.println("Enter a string");
        s = in.nextLine();
        System.out.println("You entered string " + s);

        System.out.println("Enter an integer");
        a = in.nextInt();
        System.out.println("You entered integer " + a);

        System.out.println("Enter a float");
        b = in.nextFloat();
        System.out.println("You entered float " + b);
    }
}

然后,Add在main()旁边抛出IOException

DataInputStream input = new DataInputStream(System.in);
System.out.print("Enter your name");
String name = input.readLine();
import java.util.Scanner;

public class userinput {
    public static void main(String[] args) {        
        Scanner input = new Scanner(System.in);

        System.out.print("Name : ");
        String name = input.next();
        System.out.print("Last Name : ");
        String lname = input.next();
        System.out.print("Age : ");
        byte age = input.nextByte();

        System.out.println(" " );
        System.out.println(" " );

        System.out.println("Firt Name: " + name);
        System.out.println("Last Name: " + lname);
        System.out.println("      Age: " + age);
    }
}

您可以使用Scanner获取用户输入。您可以使用正确的方法对不同的数据类型使用正确的输入验证,例如对String使用next(),对Integer使用nextInt()。

import java.util.Scanner;

Scanner scanner = new Scanner(System.in);

//reads the input until it reaches the space
System.out.println("Enter a string: ");
String str = scanner.next();
System.out.println("str = " + str);

//reads until the end of line
String aLine = scanner.nextLine();

//reads the integer
System.out.println("Enter an integer num: ");
int num = scanner.nextInt();
System.out.println("num = " + num);

//reads the double value
System.out.println("Enter a double: ");
double aDouble = scanner.nextDouble();
System.out.println("double = " + aDouble);


//reads the float value, long value, boolean value, byte and short
double aFloat = scanner.nextFloat();
long aLong = scanner.nextLong();
boolean aBoolean = scanner.nextBoolean();
byte aByte = scanner.nextByte();
short aShort = scanner.nextShort();

scanner.close();

你可以做一个简单的程序,要求用户的名字和打印任何回复使用输入。

或者让用户输入两个数字,你可以加、乘、减或除这些数字,并打印出用户输入的答案,就像计算器的行为一样。

你需要Scanner类。你必须导入java。util。scanner;在你需要使用的代码中

Scanner input = new Scanner(System.in);

Input是一个变量名。

Scanner input = new Scanner(System.in);

System.out.println("Please enter your name : ");
s = input.next(); // getting a String value

System.out.println("Please enter your age : ");
i = input.nextInt(); // getting an integer

System.out.println("Please enter your salary : ");
d = input.nextDouble(); // getting a double

看看这有什么不同:input.next();, i = input.nextInt();, d = input.nextDouble();

根据String类型,int和double类型以同样的方式变化。不要忘记代码顶部的import语句。

请参见博客文章“扫描器类和获取用户输入”。