1.3 Conditionals

Read: http://www.learnjavaonline.org/en/Conditionals

• Know boolean operators (<, >, ==, ||, &&)
• Differentiate between =, ==, and .equals()
  • = to assign a value

int num=0;

• == to check for equal number

int a=4;

if(a==4){}

• .equals() to check for equivalent Strings and other objects

String a="hello";

String b="hell"+"o";

if(a.equals(b)){}

• If, else if, else: be able to use them swiftly (more descriptions in the next lesson)

if(a<0){}

else if(a>0 && a<5){}

else{}

• Practice with provided exercise in the link (Change the variables in the first section, so that each if statement resolves as true. )

Exercise:

• Complete the following class.
• If user enters a letter grade (A,B,C,D, or F), print out a sentence with such grade ("you got a _!"). Then, give an advice to the student (Good grade, bad grade). If user enters other things, print out that you don't understand.

import javax.swing.JOptionPane;

public class Grade

{

    public static void main(String[] args)

    {

        String str=JOptionPane.showInputDialog("Enter a letter"); //gets a string from user input and stores it in the variable str

        //your code here. Complete the program

    }

}

Created: Dexin on 3/25/18

Updated: Dexin, 12/5/18