TimeBetween.java

import java.util.Scanner;
public class TimeBetween{
    public static void main(String[]args){
        //Input
        Scanner scan = new Scanner(System.in);
        System.out.print("Enter first time: ");
        String first = scan.next();
        System.out.print("Enter second time: ");
        String second = scan.next();

        int firsthour = 0;
        int firstminute = 0;
        int secondhour = 0;
        int secondminute = 0;

        //Substrings

        //First Hour Tester
        if(first.substring(0,1).equals("0")){
            firsthour = Integer.parseInt(first.substring(1,2));
        }
        else{
            firsthour = Integer.parseInt(first.substring(0,2));
        }

        //First Minute Tester
        if(first.substring(2).equals("00")){
            firstminute = 0;
        }
        else{
            firstminute = Integer.parseInt(first.substring(2));
        }

        //Second Hour Tester
        if(second.substring(0,1).equals("0")){
            secondhour = Integer.parseInt(second.substring(1,2));
        }
        else{
            secondhour = Integer.parseInt(second.substring(0,2));
        }

        //Second Minute Tester
        if(first.substring(2,3).equals("00")){
            secondminute = 0;
        }
        else{
            secondminute = Integer.parseInt(second.substring(2));
        }

        //Calculation
        int hours = secondhour-firsthour;
        int minutes = secondminute-firsthour;

        //Output
        System.out.println(hours+":"+minutes); //8:-7 output for 0700 and 1500
    }
}