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Java: All Recent Posts Grouped
Concept Learning Code Sheets View all
Resolving Class and Local Variable Name Clash #3871  (20-Mar-2018)
In Topic(s) : Data Types Variables and Constants   


class VariableNameClash
{
  static int x=10;  
  public static void main(String[] args)
  {
    int x=20;  
    System.out.println(x);
    //System.out.println(this.x);
    System.out.println(VariableNameClash.x);
  }
}

Methods to rightly use variable names when their names clash between class/static types and local types.


Variable Default Values #3867  (20-Mar-2018)
In Topic(s) : Data Types Variables and Constants   

class VarDefaultValues
{
  static byte b; 
  static short s; 
  static int i; 
  static long l; 
  static char c; 
  static double d; 
  static float f; 
  static boolean bool; 
  public static void main(String[] args)
  {
    System.out.println("Default value of byte "+b);
    System.out.println("Default value of short "+s);
    System.out.println("Default value of int "+i);   
    System.out.println("Default value of long "+l);       
    System.out.println("Default value of char "+c);           
    System.out.println("Default value of double "+d);           
    System.out.println("Default value of float "+f);           
    System.out.println("Default value of boolean "+bool);               
  }
}

Java class variables have default values. Let us experiment with that.


Variable Kinds – Local, Class and Instance Variables #3865  (20-Mar-2018)
In Topic(s) : Data Types Variables and Constants   

class VarKinds
{
  static int x=1;
  int y=2;
  public static void main(String[] args)
  {
    int z=3;
    VarKinds ob=new VarKinds();
    System.out.println(x);
    System.out.println(ob.y);
    System.out.println(z);
  }
}

Mainly used kinds Local, Class and Instance Variables are discussed here.


Variable Declaration and Initialisation #3862  (20-Mar-2018)
In Topic(s) : Data Types Variables and Constants   

class VarDecInit
{
  public static void main(String[] args)
  {
    int x;
    x=10;
    int y=20;
    int z=y;
    double d=Math.pow(2,3); 
    System.out.println(x);
    System.out.println(y);
    System.out.println(z);    
    System.out.println(d);    
  }
}

Variable declaration and initialisation varieties are explained here.


Understanding Reference data type #3859  (20-Mar-2018)
In Topic(s) : Data Types Variables and Constants   

class RefDataType
{
  int rd=5;  
  public static void main(String[] args)
  {
    RefDataType robj = new RefDataType();
    System.out.println(robj.rd);
    int ar[]={1,2};
    System.out.println(ar);
    System.out.println(ar[0]+", "+ar[1]);
  }
}

Reference data type for class object reference and array reference.


Understanding boolean data type #3850  (19-Mar-2018)
In Topic(s) : Data Types Variables and Constants   

class BooleanType
{
  public static void main(String[] args)
  {
    boolean b=true;
    //int x=b;
    if(b) System.out.println(b);
    if(b==true) System.out.println(b);
  }
}

The java boolean data type declaration and its features.


Understanding char data type #3848  (19-Mar-2018)
In Topic(s) : Data Types Variables and Constants   


class CharType
{
  public static void main(String[] args)
  {
    char a=0;
    char b=10;    
    char c=33;
    char d=65;
    char e=126;
    char f=255;    
    char g=65535;
    char h='a';
    char i='u03C0';
    System.out.println(a);
    System.out.println(b);
    System.out.println(c);
    System.out.println(d);
    System.out.println(e);
    System.out.println(f);
    System.out.println(g);
    System.out.println(h);    
    System.out.println(i);  
  }
}

The java char data type and its possible values are explained here.


Understanding byte, short, int and long types #3846  (19-Mar-2018)
In Topic(s) : Data Types Variables and Constants   

class IntTypes
{
  public static void main(String[] args)
  {
    byte bp=127;
    byte bn=-128;
    short sp=32767;
    short sn=-32768;
    int ip=2147483647;
    int in=-2147483648;
    long lp=9223372036854775807L;
    long ln=-9223372036854775808L;
    System.out.println("Largest byte type value = "+bp);
    System.out.println("Smallest byte type value = "+bn);    
    System.out.println("Largest short type value = "+sp);;      
    System.out.println("Smallest short type value = "+sn);;      
    System.out.println("Largest int type value = "+ip);;
    System.out.println("Smallest int type value = "+in);;    
    System.out.println("Largest long type value = "+lp);      
    System.out.println("Smallest long type value = "+ln);;      
  }
}

Different types of integer data types with its maximum and minimum value limits are explained with this code.


Understanding double and float data type #3840  (19-Mar-2018)
In Topic(s) : Data Types Variables and Constants   

class DoubleFloat
{
  public static void main(String[] args)
  {
    Double x=2342.34567;
    float y=2342.34567f;
    System.out.println(x);
    System.out.println(y);
    Double X=x;
    Float Y=y;    
    System.out.println("Double type max value = "+X.MAX_VALUE);      
    System.out.println("Float type max value = "+Y.MAX_VALUE);
    System.out.println("Double type size = "+X.SIZE);          
    System.out.println("Float type size = "+Y.SIZE);          
  }
}

Double and float data type declaration its max value and sizing.


Boolean Literals #3822  (13-Mar-2018)
In Topic(s) : Tokens Keywords Identifiers Literals   

class BooleanLiterals
{
  public static void main(String[] args)
  {
    boolean pass=true;
    boolean topper=false;
    if(pass)
      System.out.println("You have successfully cleared the exams.");
    if(topper)
      System.out.println("Congrats for being the topper");
    else
      System.out.println("With a little more effort you can even become a topper.");
  }
}

Use of boolean literals.


Solved ProblemsView all



Data type selection #3873 (21-Mar-2018)
In Topic(s) : Data Types Variables and Constants   

Write a program to initialise a variable with price of an item as a fractional value. Then prepare another variable to output the price multiplied with 100 so that its lowest currency denomination (LCD) value is achieved. Print the LCD price with a suitable message. Choose appropriate variable names and data types.

Write a program to initialise a variable with price of an item as a fractiona








Concept Notes and ResourcesView all







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