How to print a string with an int

Question

I am trying to get this code to run and basically solve an equation. So, I asked the user to write an equation. It looked like this:

System.out.println("Write an equation and I will solve for x.");
int answer = in.nextLine();

But I can't get the user to write a string and an int. Do I need to say String answer or int answer?

`String answer` if you want them to input an equation. You will then need to parse it, determining its operators and operands, and solve for x. — J0e3gan, Jan 09 '15 at 04:43
I am unfamiliar with parse, could you show me an example, please? — Nikki, Jan 09 '15 at 04:47
here is an example http://stackoverflow.com/questions/787735/what-is-parse-parsing — ZEE, Jan 09 '15 at 04:48
On another note, Nikki, there is no solution to `6x = 3` if you restrict `x` to being an `int`. You may want to use `float` or `double` for the solution to an equation like this one. — Dawood ibn Kareem, Jan 09 '15 at 05:25
Are you writing logic for solving equations or are you asking how to solve the equation, because the user is going to enter a equation that you will read it and pass it to some algorithm which will calculate the result (in your case value of x) and return it to you. — Naman Gala, Jan 09 '15 at 05:29

score 0 · Answer 1 · answered Jan 09 '15 at 04:49

0

An int is used when you want the user to enter a number, but here you're looking for a combination of numbers and other characters, so you will need to use a string. When you have the equation stored in a string, you can use other methods to split up the equation into something solvable, then set int answer to whatever the answer comes out to be.

answered Jan 09 '15 at 04:49

Unsolved Cypher

1,025
10
24

Just use methods to split up the equation into ints? – Nikki Jan 09 '15 at 04:53
It's hard to tell what you're asking without an example equation. Are you dealing with just one variable? – Unsolved Cypher Jan 09 '15 at 05:03

score 0 · Answer 2 · answered Jan 09 '15 at 04:55

On a simpler side, String will be required input from the user, User will enter the equation.

Then comes the complex part of solving/computing the equation.

1.) create your own parser to pass operands/operator.

2.) Provide a equation with values to some API, you can make use of MVEL or ANTLR

score 0 · Answer 3 · answered Jan 09 '15 at 07:03

Here's a little program that demonstrates one way to get the equation and divide into numeric / non-numeric values provided the equation input is space delimited. You can then determine what the non-numeric values are and proceed from there.

import java.util.Scanner;

public class SolveX{

    public static void main(String[] a){

        Scanner in = new Scanner(System.in);
        System.out.println("Write an equation and I will solve for x.");
        String input = "";

        while( in.hasNext() ){
            input = in.next();
            try{  
                double d = Double.parseDouble(input);
                System.out.println("Double found at: " + input);
                //  Do what you need to with the numeric value
            }  
            catch(NumberFormatException nfe){
                System.out.println("No double found at: " + input);
              //    Do what you need to with the non numeric value 
            }
        }
    }//end main
}//end SolveX class

How to print a string with an int

3 Answers3