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# Java

## Basic Syntax
### 1. HelloWorld

public class HelloWorld {
public static void main(String[] args) {
System.out.println("Hello, World!");
}
}

### 2. Variable and Primitive type
#### 2.1.1 int

int integerVariable = 10;

#### 2.1.2 float/double

float floatVariable = 10.5f;
double doubleVariable = 10.123;

#### 2.1.3 char

char charVariable = 'A';

[ASCII Code](https://www.ascii-code.com)
#### 2.1.4 boolean

boolean booleanVariableA = true;
boolean booleanVariableB = false;

### 3. Operators
#### 3.1.1 + , - , * , / , %

int result = 5 + 3; // addition
int result2 = 7 - 2; // subtraction
int result3 = 4 * 6; // multiplication
int result4 = 8 / 2; // division
int result5 = 10 % 3; // modulus (remainder)

### 3.1.2 compare Operators

boolean isEqual = (a == b); // equal to
boolean isNotEqual = (a != b); // not equal to
boolean isGreaterThan = (a > b); // greater than
boolean isLessThan = (a < b); // less than
boolean isGreaterOrEqual = (a >= b); // greater than or equal to
boolean isLessOrEqual = (a <= b); // less than or equal to

### 3.1.3 AND , OR , !

boolean andResult = (condition1 && condition2); // logical AND
boolean orResult = (condition1 || condition2); // logical OR
boolean notResult = !condition; // logical NOT

#### 3.3.4 位元運算符 XOR (we skip)
## String Basics
### 4.1.1 Sring Creation

String name = "Test";

### 4.1.2 Combine with other data types

### 4.1.3 String Methods
#### length()
#### equals()
#### charAt(int index)

## Conditions
### 1.1 Conditionals
#### 1.1.1 if

if (condition) {
// code block to be executed if the condition i            s true
}

#### 1.1.2 switch

switch (expression) {
case value1:
// code block for value1
break;
case value2:
// code block for value2
break;
// ... more cases
default:
// code block if none of the cases match
}

## Loops
### 2.1 Loop
#### 2.1.1 for loop

for (int i = 0; i < 5; i++) {
// code block to be executed in each iteration
}

for(char s : s.toCharArray()){
// code block to be executed in each iteration
}

#### 2.1.2 while loop

while (condition) {
// code block to be executed as long as the condition is true
}

#### 2.1.3 do-while loop

do {
// code block to be executed at least once, and then as long as the condition is true
} while (condition);

### 2.2 Break , Contiune
#### 2.2.1 Break

for(int i = 0 ; i <=100 ; i++){
if( i ==5 )
break;
System.out.println(i);
}
//Output
1
2
3
4  

#### 2.2.2 Contiune

for(int i = 0 ; i <11 ; i++){
if(i%2 ==0)
contiune;
System.out.print(i);
}
//Output
1
3
5
7
9