variables

we will mostly use:

• int for whole numbers
• double for decimal numbers
• char for single letters
• String for words or sentences
• boolean for flags

public class variables{
  public static void main(String[] args) { 
    
    //whole numbers:
    //--------------
    //byte maxByte = 127; //8-bit, ranges up from -128
    //short maxShort = 32767; //16-bit, ranges up from -32,768
    int maxInt = 2147483647; //32-bit
    //there is a 64-bit data type called long,
    //which could hold 9223372036854775807 -
    //but for now we will just use integer
     
    
    //decimal numbers:
    //----------------
    //(there is a 32-bit data type called float,
    //but for now we will just use double):
    double myDouble = 1.7976931348623157E+308; //64-bit huge
    
      
    //characters and letters:
    //----------------
    char doYouWantToLearnJava = 'y';
    String howMuchDoYouEnjoyJava = "heaps";
    
    //booleans (flags - can be true or false only):
    //----------------
    boolean iLoveJava = true;
  }

calculator

//save as calculator.java
public class calculator {
    public static void main(String[] args) { 
       int numberOne = 13;
       int numberTwo = 37;
       int answer;
       
       answer = numberOne + numberTwo;
       System.out.println(answer);
    }
}

sort

//save as sort.java
public class sort {
  public static void main(String[] args) { 
     int A, B, C, temp;
     A = 150;
     B = 180;
     C = 175;
     
     if(A>B){
         temp = B;
         B = A;
         A = temp;
     }
     
     if(B>C){
         temp = C;
         C = B;
         B = temp;
     }
     
     if(A>B){
         temp = B;
         B = A;
         A = temp;
     }
     
     System.out.println(A);
     System.out.println(B);
     System.out.println(C);
  }
}