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Calculatrice de base en Java

J'essaie de créer une calculator de base dans Java. Je suis assez novice en programmation, alors j'essaie de m'y habituer. 

import Java.util.Scanner;
import javax.swing.JOptionPane;

public class javaCalculator 
{

    public static void main(String[] args) 
    {
        int num1;
        int num2;
        String operation;


        Scanner input = new Scanner(System.in);

        System.out.println("please enter the first number");
        num1 = input.nextInt();

        System.out.println("please enter the second number");
        num2 = input.nextInt();

        Scanner op = new Scanner(System.in);

        System.out.println("Please enter operation");
        operation = op.next();

        if (operation == "+");
        {
            System.out.println("your answer is" + (num1 + num2));
        }
        if  (operation == "-");
        {
            System.out.println("your answer is" + (num1 - num2));
        }

        if (operation == "/");
        {
            System.out.println("your answer is" + (num1 / num2));
        }
        if (operation == "*")
        {
            System.out.println("your answer is" + (num1 * num2));
        }


    }
}

Ceci est mon code. Il vous demande les chiffres et les opérations, mais affiche les réponses toutes ensemble.

javacalculator
5
user2037720
Here is simple code for calculator so you can consider this
import Java.util.*;
import Java.util.Scanner;
public class Hello {
    public static void main(String[] args)
    {
        System.out.println("Enter first and second number:");
        Scanner inp= new Scanner(System.in);
        int num1,num2;
        num1 = inp.nextInt();
        num2 = inp.nextInt();
        int ans;
        System.out.println("Enter your selection: 1 for Addition, 2 for substraction 3 for Multiplication and 4 for division:");
        int choose;
        choose = inp.nextInt();
        switch (choose){
        case 1:
            System.out.println(add( num1,num2));
            break;
        case 2:
            System.out.println(sub( num1,num2));
            break;      
        case 3:
            System.out.println(mult( num1,num2));
            break;
        case 4:
            System.out.println(div( num1,num2));
            break;
            default:
                System.out.println("Illigal Operation");


        }



    }
    public static int add(int x, int y)
    {
        int result = x + y;
        return result;
    }
    public static int sub(int x, int y)
    {
        int result = x-y;
        return result;
    }
    public static int mult(int x, int y)
    {
        int result = x*y;
        return result;
    }
    public static int div(int x, int y)
    {
        int result = x/y;
        return result;
    }

}
5
Mohamud

Supprimez les points-virgules de vos instructions if, sinon le code qui suit sera libre standing et sera toujours exécuté:

if (operation == "+");
                     ^

Utilisez également .equals pour Strings, == compare les références Object:

 if (operation.equals("+")) {
10
Reimeus

CompareStrings avec equals(..) pas avec ==

if (operation.equals("+")
{
    System.out.println("your answer is" + (num1 + num2));
}
if (operation.equals("-"))
{
    System.out.println("your answer is" + (num1 - num2));
}
if (operation.equals("/"))
{
    System.out.println("your answer is" + (num1 / num2));
}
if (operation .equals( "*"))
{
    System.out.println("your answer is" + (num1 * num2));
}

Et le ; après les conditions était une déclaration vide, de sorte que la condition n'avait aucun effet.

Si vous utilisez Java 7, vous pouvez également remplacer les instructions if par un switch.
En Java <7, vous pouvez tester si operation a la longueur 1 et que vous effectuez un changement pour char [switch (operation.charAt(0))]

3
MrSmith42
import Java.util.Scanner;
public class AdditionGame {

public static void main(String[] args) {
    // TODO Auto-generated method stub

    int num1;
    int num2;
    String operation;

    Scanner input = new Scanner(System.in);

    System.out.println("Please Enter The First Number");
    num1 = input.nextInt();

    System.out.println("Please Enter The Second Number");
    num2 = input.nextInt();

    Scanner op = new Scanner (System.in);

    System.out.println("Please Enter The Operation");
    operation = op.next();

    if (operation.equals("+"))
    {
        System.out.println("Your Answer is "+(num1 + num2));
    }
    else if (operation.equals("-"))
    {
        System.out.println("Your Answer is "+(num1 - num2));
    }       
    else if (operation.equals("*"))
    {
        System.out.println("Your Answer is "+(num1 * num2));
    }   
    else if (operation.equals("/"))
    {
        System.out.println("Your Answer is "+(num1 / num2));
    }
}

}

0
Ronak Mandania

Exemple de programme Java pour faire une calculatrice simple: 

import Java.util.Scanner;

public class Calculator
{
public static void main(String args[])
{
    float a, b, res;
    char select, ch;
    Scanner scan = new Scanner(System.in);

    do
    {
        System.out.print("(1) Addition\n");
        System.out.print("(2) Subtraction\n");
        System.out.print("(3) Multiplication\n");
        System.out.print("(4) Division\n");
        System.out.print("(5) Exit\n\n");
        System.out.print("Enter Your Choice : ");
        choice = scan.next().charAt(0);

        switch(select)
        {
            case '1' : System.out.print("Enter Two Number : ");
                a = scan.nextFloat();
                b = scan.nextFloat();
                res = a + b;
                System.out.print("Result = " + res);
                break;
            case '2' : System.out.print("Enter Two Number : ");
                a = scan.nextFloat();
                b = scan.nextFloat();
                res = a - b;
                System.out.print("Result = " + res);
                break;
            case '3' : System.out.print("Enter Two Number : ");
                a = scan.nextFloat();
                b = scan.nextFloat();
                res = a * b;
                System.out.print("Result = " + res);
                break;
            case '4' : System.out.print("Enter Two Number : ");
                a = scan.nextFloat();
                b = scan.nextFloat();
                res = a / b;
                System.out.print("Result = " + res);
                break;
            case '5' : System.exit(0);
                break;
            default : System.out.print("Wrong Choice!!!");
        }
    }while(choice != 5);       
}
}
0
Linkon