cse 1325 Object Oriented Programming
Syllabus
Email: [email protected]
Office hours: tuesday 10-12
ERB 545
Midterm exam 09 october 2023 11am
Final exam date 27 november 2023 11am
WORA
- Write once, run anywhere
- Java is useable everywhere
Difference between structs and classes
Structures
Struct Student
{
Int ID,
String Name,
String Address,
}
Student S1;
S1.ID = 1001;- You create objects from structures
- When creating an object you can access each thing inside the struct with
- S.
- Then you can do ID, Name, and address
- I.E. S.
- If the data is protected the class that inherits it can only access it
- If its public then anything can access it
- Every line of code we put in classes
- Packages are like folders
- You put all the classes in there for what you need it for
Class Student
{
Private int ID; //this cannot be accessed through main
Public String Name, Add; // can be accessed anywhere easily
}
Student S;Java
JVM
Java virtual machine
- JVM is an interpreter of Java Byte code
JRE
- Java Runtime Enviornment
- Basically it executes the code, not your actual system
- Doing it this way makes java universal to run anywhere if JRE is on a system
JDK
- Java Development Kit
- Pretty much where all the libraries are
- JVM most likely pulls from here to link the libraries in your classes that you imported
- **In Java, binary starts with 0b, octal starts with 0, and hexadecimal starts with 0x. **
- When of course declaring an int
- I.e. int Binary = 0b1001;
Data types
Primitive
- Int ( 4 bytes)
- Byte (1 byte)
- Long (8 bytes) a = 1_000_000_000
- Short (2 bytes)
- Double
- Float (requires an F at the end)
- Char
- Boolean
NonPrimative
* String
* Strings are a class
* Array
Int a = 0b00001010;
println(a);
Int b = 0xAF15;
println(b);
Int c = 0753;
println(c);
String username = “Wick”;
println(username);
println(“hello mr” + username);Java operators
- Arithmetic
- / %
- Logical 2. && || !
- Relational
- Unary 3. ++ -- - + 4. ++a (increments before) a++ (increments after)
- Bitwise 5. ^ | &
- Assignment operators 6. = += -= *= /= %=
Int a =2, b=5;
println(a + b);
int i = 5; //shortcut for System.out is
//<span style="text-decoration:underline;">Sysout</span> <span style="text-decoration:underline;">ctrl</span>+space
System.**_out_**.println(i);
Int a= 2, b = 3, c = 4
Bool c = (a < b && a < c);Instance of
String str = “Hello”;
Boolean b = str instanceof String; //checks if our variable is a certain data type we check for
Ternary if
Int a = (b > c) ? 10 : 20;
Set a = to 10 if true or 20 if false
Scanner class
Import java.util.Scanner;
We need to create objects from these classes to use whatever they offer to us what we want.
Scanner input = new Scanner(System.in);
Int n =input.nextint():
… use n however you would like
.next_(data type)
.nextint()
.nextdouble()
.next boolean()
.next() (only scans up to the space)
.nextln() (scans in the whole line)C++
#include<iosstream>
Using namespace std;
Int main()
{
Cout << “Hello World”;
Return 0;
}Math class
- Min
- Max
- Absolute value
- Power
- Square root
We call it like this
Math.abs(a); <- absolute value
Math.min(b, c);
.max
.sqrt
R = a/(Math.pow(c, 20)) + x*yIf statements (Same as C)
If ( a > b )
{
//Do something will ya
}
Else if ( a < b )
{
// do somethin elseeee
}
Else
{
// default do somethin or somethin
}Switch statements
Old switch
Int a = 2;
switch (a)
{
case 1:
println(“You entered a 1”);
Break;
case 2:
println(“You entered a 2”);
break;
case 3:
println(“You entered a 3”);
break;
Default:
println(“unknown”);
break;
}New switch
int a = 2
switch(a)
{
case 1,2,3 -> System.out.println("1, 2 or 3");
case 4, 5 -> System.out.println("4 or 5");
case 6 -> System.out.println("6");
default -> System.out.println("unknown");
}import java.util.Scanner;
public class calculator
{
public static void main(String[] args)
{
Scanner input = new Scanner(System.in);
double a, b;
char op;
System.out.println("Welcome to a simple java calculator \n The opperands are (+) (-) (/) (*) (%) (0) = minimum (1) = max \n");
System.out.print("Enter the first number: ");
a = input.nextDouble();
System.out.print("Enter an operand: ");
op = input.next().charAt(0);
System.out.print("Enter the second number: ");
b = input.nextDouble();
System.out.println("\n----------------------\n");
switch (op) {
case '+':
System.out.println(a + " + " + b + " = " + (a + b));
break;
case '-':
System.out.println(a + " - " + b + " = " + (a - b));
break;
case '*':
System.out.println(a + " * " + b + " = " + (a * b));
break;
case '/':
System.out.println(a + " / " + b + " = " + (a / b));
break;
case '%':
System.out.println(a + " % " + b + " = " + (a % b));
break;
case '1':
System.out.println("maxium value is: " + Math.max(a, b));
break;
case '0':
System.out.println("minium value is: " + Math.min(a, b));
break;
default:
break;
}
System.out.println("\n----------------------\n");
System.out.print("Enter an int: ");
int c = input.nextInt();
int ones, tens, hundreds, temp;
temp = c;
ones = c % 10;
// System.out.println("Ones = " + ones);
tens = (c / 10) % 10;
// System.out.println("Tens = " + tens);
hundreds = c / 100;
// System.out.println("Hundreds = " + hundreds);
c = ones * 100 + tens * 10 + hundreds;
// System.out.println("your int = " + c);
String str = (c == temp) ? "a Palindrome" : "Not a palindrome!";
System.out.println("your int is " + str);
System.out.println("\n----------------------\n");
System.out.println("please input first value: ");
int d = input.nextInt();
System.out.println("please input second value: ");
int e = input.nextInt();
if (d > e)
{
temp = d;
d = e;
e = temp;
}
System.out.println(d + " " + e);
}
}Creating a factorial loop
F = 5!
5 * 4 * 3 * 2 * 1
Using a for loop
Int f = 1, i, n;
Input -> n
//increments
For ( i = 1; i < n, i++) { F = f * i; }
//decrements For ( i = n; i >= 1; i--) { F= f*i; }