1. Nahla Abuel-ola / WIT

2. Your First Program in Java: Printing a Line of Text (Cont.)
System.out.println method
Displays (or prints) a line of text in the command window.
The string in the parentheses the argument to the method.
Positions the output cursor at the beginning of the next line in the command window.
Most statements end with a semicolon.
Nahla Abuel-ola / WIT

3. Obtaining Variables as input From the User
1. Import java.util.Scanner;
2. Create an object ( a copy from the Scanner class):
Scanner obj = new Scanner (system.in);
3. Print your question:
System.out.println(“ please enter the number);
4. Store the number in the obj variable:
Obj = number.nextInt();
Nahla Abuel-ola / WIT

4. Nahla Abuel-ola / WIT

5. Arithmetic Operations
Nahla Abuel-ola / WIT

6. Arithmetic Operations
Nahla Abuel-ola / WIT

7. Relational and conditional operators
Nahla Abuel-ola / WIT

8. Arithmetic (Cont.) Rules of operator precedence
Multiplication, division and remainder operations are applied first.
If an expression contains several such operations, they are applied from left to right.
Multiplication, division and remainder operators have the same level of precedence.
Addition and subtraction operations are applied next.
If an expression contains several such operations, the operators are applied from left to right.
Addition and subtraction operators have the same level of precedence.
When we say that operators are applied from left to right, we are referring to their associativity.
Some operators associate from right to left.
Complete precedence chart is included in Appendix A.
Nahla Abuel-ola / WIT

9. Nahla Abuel-ola / WIT

10. Nahla Abuel-ola / WIT

11. Java Basics: Expressions
Examples:
5 / 2 yields an integer 2.
5.0 / 2 yields a double value 2.5
5 % 2 yields 1 (the remainder of the division)
Remainder is very useful in programming.
an even number % 2 is always 0 and
an odd number % 2 is always 1.
So you can use this property to determine whether a number is even or odd
Nahla Abuel-ola / WIT

12. Nahla Abuel-ola / WIT

13. Type Casting
Two types
Implicit—also called "Automatic"
Done FOR you, automatically 17 / 5.5
Explicit type conversion
Programmer specifies conversion with cast operator (double)17 / (double)myInt / myDouble
Explicitly "casts" or "converts" intVar to double type
Result of conversion is then used
Can add ".0" to literals to force precision arithmetic, but what about variables?
We can’t use "myInt.0"!
Nahla Abuel-ola / WIT

14. Compound Assignment Operations
Nahla Abuel-ola / WIT

15. Increment and Decrement Operators
Unary increment operator, ++, adds one to its operand
Unary decrement operator, --, subtracts one from its operand
An increment or decrement operator that is prefixed to (placed before) a variable is referred to as the prefix increment or prefix decrement operator, respectively.
An increment or decrement operator that is postfixed to (placed after) a variable is referred to as the postfix increment or postfix decrement operator, respectively.
Nahla Abuel-ola / WIT

16. Increment and Decrement Operators
Nahla Abuel-ola / WIT