How to convert a improper fraction to a mixed fraction using java

Question

I am trying to convert a improper fraction to a mixed fraction using my calculator that I have developed for a course that I am taking. I'm stuck on how to go about this. Here is my code. Any help would be greatly appreciated

    package fractioncalc;

import java.util.Scanner;
public class fractioncalc2 {
    public static void main(String[] args) {

        Scanner scan = new Scanner(System.in);

        System.out.println("Please input your equation");

        String input = scan.nextLine().replaceAll(" ", "");
        System.out.println(input);
        boolean add = input.contains("+");
        boolean sub = input.contains("-");
        boolean multi = input.contains("*");

    //add
    if (add) {
        String Nume1 = input.substring(0,input.indexOf("/"));
        String Demo1 = input.substring(input.indexOf("/") + 1, input.indexOf("+"));
        System.out.println(Demo1);
        String Nume2 = input.substring(input.indexOf("+") + 1,input.lastIndexOf("/"));
        String Demo2 = input.substring(input.lastIndexOf("/") + 1, input.length());

        int num1 = Integer.parseInt(Nume1);
        int den1 = Integer.parseInt(Demo1);
        int num2 = Integer.parseInt(Nume2);
        int den2 = Integer.parseInt(Demo2);
        int numans = (num1*den2+num2*den1);
        int denans = (den1*den2);

        System.out.println("your answer is" +  numans + "/" + denans);
        }


    //subtract
    else if (sub) {
        String Nume1 = input.substring(0,input.indexOf("/"));
        String Demo1 = input.substring(input.indexOf("/") + 1, input.indexOf("-"));
        String Nume2 = input.substring(input.indexOf("-") + 1,input.lastIndexOf("/"));
        String Demo2 = input.substring(input.lastIndexOf("/") + 1, input.length());

        int num1 = Integer.parseInt(Nume1);
        int den1 = Integer.parseInt(Demo1);
        int num2 = Integer.parseInt(Nume2);
        int den2 = Integer.parseInt(Demo2);
        int numans = (num1*den2-num2*den1);
        int denans = (den1*den2);

        System.out.println("your answer is" +  numans + "/" + denans);
        }


    //multiply  
    else if (multi) {
        String Nume1 = input.substring(0,input.indexOf("/"));
        String Demo1 = input.substring(input.indexOf("/") + 1, input.indexOf("*"));
        String Nume2 = input.substring(input.indexOf("*") + 1,input.lastIndexOf("/"));
        String Demo2 = input.substring(input.lastIndexOf("/") + 1, input.length());

        int num1 = Integer.parseInt(Nume1);
        int den1 = Integer.parseInt(Demo1);
        int num2 = Integer.parseInt(Nume2);
        int den2 = Integer.parseInt(Demo2);
        int numans = (num1*den2*num2*den1);
        int denans = (den1*den2);

        System.out.println("your answer is" +  numans + "/" + denans);
        }


    //divide
    else {
        String b = input.substring(0, input.lastIndexOf("/"));
        String c = input.substring(input.indexOf("/")+1);
        String Nume1 = b.substring(0,input.indexOf("/"));
        String Demo1 = b.substring(input.indexOf("/") + 1, input.lastIndexOf("/")-2);
        String Nume2 = c.substring(input.indexOf("/") + 1,input.lastIndexOf("/")-2);
        String Demo2 = c.substring(input.lastIndexOf("/") - 1);

        int num1 = Integer.parseInt(Nume1);
        int den1 = Integer.parseInt(Demo1);
        int num2 = Integer.parseInt(Nume2);
        int den2 = Integer.parseInt(Demo2);
        int numans = (num1*den2);
        int denans = (den1*num2);

        System.out.println("your answer is:  " +  numans + "/" + denans);

    }
    }
}

Answer 1

Consider that a mixed fraction has two parts: a whole number and a fraction. The whole number is the amount of times numerator fits into denominator wholly (which is the floored value of numerator / denominator ). The numerator to the fraction is the remainder of this division, and the denominator does not change.

Thus, the algorithm would be (pseudocode):

Whole = Floor(Numerator / Denominator)
Part = Numerator % Denominator
Print(Whole + " " + Numerator + "/" + Denominator)

Note the % symbol used here. This is referred to as modulo, and represents the remainder of the division of the two numbers. Java uses the same symbol.

For an implementation of Floor , look into the Java Math class.