Announcements

1. Announcements • B7 tutorial today 1100-1200 in CS103 • In CSE department • Ask at entry desk for direction to CS103

2. Unary and binary operators • Operators acting on a single variable or an expression are called unary operators • Example: logical NOT, unary plus, unary minus boolean x = true; boolean y = !x; // unary logical NOT int z = 23; int w = +z; // unary plus int k = -z; // unary minus or negation int j = -z-20; // what is j: -43 or -3? int r = -(z-20); // what is r?

3. Unary and binary operators • Operators acting on two variables or expressions are called binary operators • Example: add (+), subtract (-), multiply (*), … • Example of boolean operators (unary and binary) boolean x = true; boolean y = !x && x; boolean z = !(y || x); boolean w = !y && !x; boolean k = !(y && x); boolean p = !y || !x;

4. Examples Instructor: Mainak Chaudhuri mainakc@cse.iitk.ac.in

5. Printing characters class printcharacter{ public static void main(String arg[]){ char grade=‘A’; System.out.println(grade); // prints A System.out.println((int)grade); // prints 65 System.out.println(grade+’B’); // prints 131 System.out.println(grade+1); // prints 66 System.out.println((char)(grade+1)); // prints B } } • Notice the type cast • Notice the automatic type conversion

6. Printing characters class printcharacter{ public static void main(String arg[]){ char grade=‘A’; System.out.println(grade++);// prints A System.out.println(grade); // prints B } } • Post-increment

7. Printing characters class printcharacter{ public static void main(String arg[]){ char grade=‘A’; System.out.println(++grade);// prints B System.out.println(grade); // prints B } } • Pre-increment

8. More type cast class castExample{ public static void main(String arg[]){ double x=Math.PI; // Call to Math class double y=-Math.PI; System.out.println(“Value of PI is: ” + x); System.out.println((int)x); // prints 3 System.out.println((int)y); // prints -3 } }

9. Celsius to Fahrenheit class CToF{ public static void main(String arg[]){ double C = 40; double F; F = (C/5.0)*9.0 + 32; System.out.println(C + “Celsius is same as ” + F + “ Fahrenheit”); } }