Coding

Day 9 of #100daysofcode Learned about Java method signatures and overloading today.. static is optional.. add parameters to change the signature to overload the method. Modifiers and return types are not part of the signature. #learninpublic #100daysofcodechallenge

Today I learned about the .equals() method for comparing strings to find out if they are equal or not. Using the == equality operator returns true if both objects are the same but it using a reference in memory to compare the two instead of the value of the string. So the best way to do it would be …

String string1 = "Hello";
String string2 = "Hello";
String string3 = "Another String";
System.out.println(myStr1.equals(string2)); // Returns true because they are equal
System.out.println(myStr1.equals(string3)); // false

// instead of doing the following 

string1 == string 2

I also went over how to use the .substring() method to select the characters in a string. For example:

String string = new String("Lets Code");

// We can use the .substring() method to select a part of a string.

System.out.println(string.substring(8));

// This will print out: de because the index of d is 8 and the substring method prints out the rest of the string. 

// You can also select a beginning and end to pull out just the middle of a string:

System.out.println(string.substring(2, 4));

// This would pring out: et because it selects 2nd index which is "e" and the last index it selects will print the letter before it "t" because the character at index 4 is "s".

I also made a basic interest calculator and a compound interest calculator to practice. Here is the code.

package com.skillstorm.general;

import java.util.Scanner;

public class InterestCalculator {
	
	public static void main(String[] args) {
		// Scanner to read user input
		Scanner in = new Scanner(System.in);
		
		System.out.println("-----------------------------------------------------------------------");
		System.out.println("        -   Casey Spaulding's Simple Interest Calculator  -             ");
		System.out.println("-----------------------------------------------------------------------");
		System.out.println("");
		System.out.println("Welcome to the Simple Interest Calculator! ");
		System.out.println("");
		
		System.out.println("Please enter your principle:");
		
		System.out.println("");
		double principle = in.nextDouble();
		
		System.out.println("Thank you. Next, please enter your rate as a percentage:");
		
		System.out.println("");
		double rate = in.nextDouble();
		
		System.out.println("Next, please enter the amount of years:");
		double years = in.nextDouble();
		
		// Calculate simple interest 
		double simpleInterest = (principle * rate * years) / 100;
		

		// Result
		System.out.println("Compound Interest Amount = $" + simpleInterest);
		
		
		//Part 2
		System.out.println("-----------------------------------------------------------------------");
		System.out.println("        -   LEVEL 2! Casey Spaulding's Compound Interest Calculator  -             ");
		System.out.println("-----------------------------------------------------------------------");
		System.out.println("");
		System.out.println("Welcome to the Compound Interest Calculator! ");
		System.out.println("");
		
		System.out.println("Please enter your principle:");
		
		System.out.println("");
		double principle2 = in.nextDouble();
		
		System.out.println("Thank you. Next, please enter your rate as a percentage:");
		
		System.out.println("");
		double rate2 = in.nextDouble();
		
		System.out.println("Next, please enter the amount of years:");
		double years2 = in.nextDouble();
		
		System.out.println("Enter the time interest is compounded per year: ");
		double n = in.nextDouble();
		
		// Calculate compound interest 
	
		
		double amount = principle2 * Math.pow(1 + (rate / n),  n * years);
		double compoundInterest = amount - principle2;
		
		// Result
		System.out.println("Compound Interest after " + years + " years is: = " + compoundInterest);
		
		System.out.println("");
		System.out.println("Thank you for trying my program! Have a great day!");
		
	}

}