AP Computer Science

1. AP Computer Science Anthony Keen

2. Computer 101 • What happens when you turn a computer on? • BIOS tries to start a system loader • A system loader tries to start an operating system.

3. Java 101 • What happens when you run a program? • You tell the operating system to run a program called “java.exe” with a command line argument, your program. • Java starts up and then calls your main method.

4. Where does a program start? • public static void main(String[] args) • public = anyone can call this method • static = you don’t need an instance to call this method • void = this method doesn’t return anything • main = the name of the method • String[] = this function takes an array of Strings as its parameter • args = the name of our array

5. Primitives • int • Holds an Integer • float, double • Holds a decimal value • char • Holds a single character • boolean • Holds “true” or “false”

6. Sequential Programming • The statements within a function (like main) are executed in order.

7. Conditional Statements • if(boolean){ // stuff} • if the boolean is true, then we execute the code inside the curly braces

8. Conditional Statements • if(boolean){ // stuff}else{ // different stuff} • if the boolean is false, then we execute the code inside the else’s curly braces

9. Conditional Statements • switch(int){ case 0: // stuff break; case 1: // other stuff break; default: // default stuff}

10. Looping Structures • while (boolean){ // Stuff} • While the boolean value is true, we will keep doing whatever is inside the while’s curly braces.

11. Looping Structures • Typical Use: • int count = 0;while (count < 10){ // Stuff count++; // count = count + 1;}

12. Looping Structures • for (initialize; condition; increment){ // Stuff}

13. Looping Structures • Typical use • for (int i = 0; i < 10; i++){ // Stuff}

14. Input / Output • Input • JOptionPane.showInputDialog ( … ) • Output • System.out.print ( … ) • System.out.println ( … ) • Escape Codes • \n = New Line • \t = Tab

15. In Review • Primitives • Sequential Programming • Conditional Statements • Looping Structures • Input / Output

16. Operators • =, is assigned to • +, add numbers or concatenate Strings • -, subtract numbers • *, multiply numbers • /, divide numbers • %, divide numbers and give the remainder

17. Logic Operators • &&, AND • ||, OR • ==, equal to • !=, not equal to • &, bitwise AND • |, bitwise OR • <, less than • >, greater than

18. What else have we covered?