AP CSA Unit 2: Objects

object

a data type that is created in Java

Math class

stores common numbers used in mathematical calculations and methods that have mathematical functions

static method

belong to a class but not to any instances of that specific class

can be called without class’s instance or object

Math.abs(x)

gets the absolute value of ‘x’ ; the return value is always positive

Math.pow(x,y)

does ‘x’ to the power of ‘y’ (x^y); the answer will always be a double(decimal) value

Math.PI

stores the value for pi: 3.141592653…

charAt(int x)

returns the char at the given index of ‘x’

contains(String s)

returns true when received string is within the called string, false otherwise

endsWith(String s)

returns true when received string ends with called string, false otherwise

equals(String s)

returns true when the two strings are equal, false otherwise

equalsIgnoreCase(String s)

returns true when the two strings are equal ignoring the case( lower or upper), false otherwise

public class Example{
public static void main(String[] args){
String s = "I like apples";
String g = "ILIKEAPPLES";
//What is returned from this line of code?
System.out.println(s.equals(g));
}
}

false

public class Example{
public static void main(String[] args){
String s = "I like apples";
String g = "ILIKEAPPLES";
//What is returned from this line of code?
System.out.println(toLowerCase(g));
}
}

ilikeapples

public class Example{
public static void main(String[] args){
int x = 2;
int y = 10;

int z = Math.pow(y,x);
System.out.println(z);
}
}

100.00

public class Example{
public static void main(String[] args){
int x = 2;
int y = -10.9;

int z = Math.abs(y);
//what is printed from this program
System.out.println(z);
}
}

10.9

public class Example{
public static void main(String[] args){
String hi  = "hello, John Harvard";

//what is printed from this program?
System.out.println(hi.charAT(7));
}
}

J