private static boolean hasAllNumbers(String promptInput) {
		//We will use a for loop to go through each character in the string
		for (int i = 0; i < promptInput.length(); i++) {//If a non-number is detected we will return a false as the boolean value
			if (promptInput.charAt(i) == '-'){
				continue;
			}
			if (!Character.isDigit(promptInput.charAt(i))) {//<--this checks if a non-number is detected
				return false;//<--if a non-number character is detected then we will return false and exit the method
			}
		}
		return true;//<--if all the characters in the string are numbers then we will return true
	}//end of private method hasAllNumbers