Thread: reading a string from input

Hi so I am wondering how it would be possible to read a string from input. for instance:

public class TestInput1{
 
    public static void main (String[]args){
    double firstNo = readDouble("First number?");
    int operator = readInt("Operator - type 1 for *, 2 for +, 3 for -, or 4 for /");
    Double secondNo = readDouble("Second number?");
    if (operator == 1) {
        System.out.println(firstNo + " times " + secondNo + " = " + (firstNo*secondNo));
    }
    else if (operator == 2){
        System.out.println(firstNo + " plus " + secondNo + " = " + (firstNo+secondNo));
    }
    else if (operator == 3){
        System.out.println(firstNo + " minus " + secondNo + " = " + (firstNo-secondNo));
    }
    else if (operator == 4){
        System.out.println(firstNo + " divided by " + secondNo + " = " + (firstNo/secondNo));
    }
    }
 
    public static int readInt(String prompt){
System.out.println(prompt);
java.util.Scanner keyboard = new java.util.Scanner(System.in);
return keyboard.nextInt();
}
public static String readString(String prompt){
System.out.println(prompt);
java.util.Scanner keyboard = new java.util.Scanner(System.in);
return keyboard.nextLine();
}
public static double readDouble(String prompt){
System.out.println(prompt);
java.util.Scanner keyboard = new java.util.Scanner(System.in);
return keyboard.nextDouble();
}
}

When I first wrote this, I had it so that the user typed in the actual operator e.g. * or + however when I went to check the variable like this:

public class TestInput1{
 
    public static void main (String[]args){
    double firstNo = readDouble("First number?");
    String operator = readString("Operator --> *, +, -, or /");
    Double secondNo = readDouble("Second number?");
    if (operator == *) {
        System.out.println(firstNo + " times " + secondNo + " = " + (firstNo*secondNo));
    }
    else if (operator == +){
        System.out.println(firstNo + " plus " + secondNo + " = " + (firstNo+secondNo));
    }
    else if (operator == -){
        System.out.println(firstNo + " minus " + secondNo + " = " + (firstNo-secondNo));
    }
    else if (operator == /){
        System.out.println(firstNo + " divided by " + secondNo + " = " + (firstNo/secondNo));
    }
    }
 
    public static int readInt(String prompt){
System.out.println(prompt);
java.util.Scanner keyboard = new java.util.Scanner(System.in);
return keyboard.nextInt();
}
public static String readString(String prompt){
System.out.println(prompt);
java.util.Scanner keyboard = new java.util.Scanner(System.in);
return keyboard.nextLine();
}
public static double readDouble(String prompt){
System.out.println(prompt);
java.util.Scanner keyboard = new java.util.Scanner(System.in);
return keyboard.nextDouble();
}
}

it didn't like it, and wouldn't check the variable, an error just appeared. I didn't post this in "what's wrong with my code?" because I solved the problem, but I would like to know how to solve this in future without the crude int variable instead.
thanks,
Skeptile

It would help if you compared strings using .equals() instead of ==