A simple Hello world Program

When we write a java program .. it is saved with the file name  ClassName.java(Make sure the extension is .java. the Classname.java file is compiled using the java compliler..
If the file complies successfully then a class file of the same name (Classname.class) will be generated.then the generated class file is executed .

SO lets start with the official "Hello world program"

Hello World Program

class HelloWorld    //Declare name of the main class, first lettershould becapital
{
public static void main(String arg[]])
{
System.out.println("Hello world");                     //Prints output on the screen
System.out.print("Welcome to Codsters, Clear your concepts and logics");
}
}

Java Introduction

Java is one of the most popular and most widely used programming language used in million of devices all around the globe. Java is widely used because of its features that it provides to the programmer can make applications and others software that provides easy and attractive user interface.

Java is an object oriented programming language that works on the basis of classes and objects. It follows bottom up approach during the execution of the program.

Following are some of the features of Java:

Inheritance : It is the process of creating the new classes and using the behavior of the existing classes by extending them to use the existing code and adding the additional features in the child class if needed along with the features of base class.Base classis the classfrom which the child class inherits or extends the features.

Encapsulation: : It is the mechanism of combining the information and providing the abstraction.

Polymorphism: :   It is the ability to take multiple forms, Polymorphism is the way of providing the different oprations to the functions having the same name but performing different tasks.

Dynamic binding :   It is the way of providing the maximum functionality to a program about the specific type at runtime.

 

POP operation on stack

#include<stdio.h>
#include<conio.h>
void main()
{
int stack[10]={1,2,3,4,5};
int i,n,item,top=4;
do
{
if(top<0)
{
printf("Underflow");
getch();
break;
}
else
{
top=top-1;
printf("\n\nStack elements are");
for(i=top;i>=0;i--)
{
printf("\n%d",stack[i]);
}
}
printf("\n\nDo you want to delete more elements from stack(1 for yes 2 for no)");
scanf("%d",&n);
}
while(n==1);
}

PUSH Operation on stack

#include<stdio.h>
#include<conio.h>
void main()
{
int stack[10];
int i,n,max=9,top=-1,item;
clrscr();
do
{
if(top==max)
{
 printf("\nOVERFLOW");
 printf("Press any key to continue");
 getch();
 break;
}
else
{
 top=top+1;
 printf("Enter the element to be inserted");
 scanf("%d",&item);
 stack[top]=item;
 printf("Stack elements are");
 for(i=top;i>=0;i--)
 {
 printf("\n%d",stack[i]);
 }
}
printf("\n\nDo you want to insert more element(Press 1 for Yes 2 for No");
scanf("%d",&n);
}
while(n==1);
}

Multiplication of two matrices

#include<stdio.h>
#include<conio.h>
void main()
{
int i,j,a[3][3],b[3][3],mul[3][3];
printf("Enter the elements of array A\n");
for(i=0;i<=2;i++)
{
for(j=0;j<=2;j++)
{
printf("\na[%d][%d] = ",i,j);
scanf("%d",&a[i][j]);
}
printf("\n");
}

printf("\nEnter the elements of array B\n");
for(i=0;i<=2;i++)
{
for(j=0;j<=2;j++)
{
printf("\na[%d][%d] = ",i,j);
scanf("%d",&b[i][j]);
}
printf("\n");
}

printf("\n\nThe elements of array A are\n");
for(i=0;i<=2;i++)
{
for(j=0;j<=2;j++)
{
printf("\na[%d][%d] = %d ",i,j,a[i][j]);
}
printf("\n");
}

printf("\n\nThe elements of array B are\n");
for(i=0;i<=2;i++)
{
for(j=0;j<=2;j++)
{
printf("\na[%d][%d] = %d ",i,j,b[i][j]);
}
printf("\n");
}


printf("\n\nMultiplication of two matrices is\n");
for(i=0;i<=2;i++)
{
for(j=0;j<=2;j++)
{
mul[i][j]=a[i][j]*b[i][j];
printf("\na[%d][%d] = %d ",i,j,mul[i][j]);

}
printf("\n");
}

getch();
}

Diffference of two matrices

#include<stdio.h>
#include<conio.h>
void main()
{
int i,j,a[3][3],b[3][3],diff[3][3];
printf("Enter the elements of array A\n");
for(i=0;i<=2;i++)
{
for(j=0;j<=2;j++)
{
printf("\na[%d][%d] = ",i,j);
scanf("%d",&a[i][j]);
}
printf("\n");
}

printf("\nEnter the elements of array B\n");
for(i=0;i<=2;i++)
{
for(j=0;j<=2;j++)
{
printf("\na[%d][%d] = ",i,j);
scanf("%d",&b[i][j]);
}
printf("\n");
}

printf("\n\nThe elements of array A are\n");
for(i=0;i<=2;i++)
{
for(j=0;j<=2;j++)
{
printf("\na[%d][%d] = %d ",i,j,a[i][j]);
}
printf("\n");
}

printf("\n\nThe elements of array B are\n");
for(i=0;i<=2;i++)
{
for(j=0;j<=2;j++)
{
printf("\na[%d][%d] = %d ",i,j,b[i][j]);
}
printf("\n");
}


printf("\n\ndiffrence of two matrices is\n");
for(i=0;i<=2;i++)
{
for(j=0;j<=2;j++)
{
diff[i][j]=a[i][j]-b[i][j];
printf("\na[%d][%d] = %d ",i,j,diff[i][j]);

}
printf("\n");
}

getch();
}

Addition of two Matrices

#include<stdio.h>
#include<conio.h>
void main()
{
int i,j,a[3][3],b[3][3],sum[3][3];
printf("Enter the elements of array A\n");
for(i=0;i<=2;i++)
{
for(j=0;j<=2;j++)
{
printf("\na[%d][%d] = ",i,j);
scanf("%d",&a[i][j]);
}
printf("\n");
}

printf("\nEnter the elements of array B\n");
for(i=0;i<=2;i++)
{
for(j=0;j<=2;j++)
{
printf("\na[%d][%d] = ",i,j);
scanf("%d",&b[i][j]);
}
printf("\n");
}

printf("\n\nThe elements of array A are\n");
for(i=0;i<=2;i++)
{
for(j=0;j<=2;j++)
{
printf("\na[%d][%d] = %d ",i,j,a[i][j]);
}
printf("\n");
}

printf("\n\nThe elements of array B are\n");
for(i=0;i<=2;i++)
{
for(j=0;j<=2;j++)
{
printf("\na[%d][%d] = %d ",i,j,b[i][j]);
}
printf("\n");
}


printf("\n\nSum of two matrices is\n");
for(i=0;i<=2;i++)
{
for(j=0;j<=2;j++)
{
sum[i][j]=a[i][j]+b[i][j];
printf("\na[%d][%d] = %d ",i,j,sum[i][j]);

}
printf("\n");
}

getch();
}
                               

Binary Search

Binary search technique is more efficient than the linear search. In binary search each and every element is not traversed to find the required element.
The main limitation of binary search technique is that it can process only sorted data.The data need to be in sorted form so that binary search can be applied to it.If data is not sorted then it needs to be sorted first.
In Binary search the middle element is found first. Basically there are three values required.
Upper_bound (ub),Lower_bound(lb),Middleelemnt(mid)
mid=(ub+lb)/2;
if the middle element is less than the element to be searched then
lb=mid+1..
 and id middle element is greater than the element to be searched then.
ub=mid-1;

Program for Binary Search

#include<stdio.h>
#include<conio.h>
void main()
{
int a[10];
int flag,n,i,item,mid,lb,ub;
clrscr();
printf("Enter the number of elements you wnat to enter");
scanf("%d",&n);
printf("\nEnter the elements of arrayin sorted form\n");
for(i=0;i<n;i++)
{
 printf("a[%d] =",i);
 scanf("%d",&a[i]);
}

printf("\nThe elements of array are");
for(i=0;i<n;i++)
{
 printf("\na[%d] = %d",i,a[i]);
}

printf("\nEnter the elements of array to be searched");
scanf("%d",&item);

lb=0;
ub=n-1;
while(ub>=lb)
{
mid=(ub+lb)/2;

if(item==a[mid])
{
flag=1;
break;
}
else
{
if(item>a[mid])
{
 lb=mid+1;
}
else
{
ub=mid-1;
}
}
}
if(flag==1)
{
printf("\n Item %d found at location a[%d]",item,mid);
}
else
{
printf("\nItem not found");
}
getch();
}

                                 

Linear search

Linear search is one of the searching technique using a simple logic of matching each element of the array with the item to be searched.Linear search can be performed on any type of array.. the array may be sorted or unsorted..it works on both.
This method s not efficient when the number of elements is very large. When processing huge amount of data this method gets very slow because it is very time and resource  consuming as each and every element is traversed thus is not used for processing huge data.


#include<stdio.h>
#include<conio.h>
void main()
{
int a[10];
int n,i,item,k=0,j;
clrscr();
printf("Enter the number of elements you wnat to enter");
scanf("%d",&n);
printf("\nEnter the elements of array\n");
for(i=0;i<n;i++)
{
 printf("a[%d] =",i);
 scanf("%d",&a[i]);
}

printf("\nThe elements of array are");
for(i=0;i<n;i++)
{
 printf("\na[%d] = %d",i,a[i]);
}

printf("\nEnter the elements of array to be searched");
scanf("%d",&item);
for(k=0;k<n;k++)
{
if(a[k]==item)
{
j=1;
break;
}
}
if(j==1)
printf("success");
else
printf("no success");
getch();
}

Bubble Sort

#include<stdio.h>
#include<conio.h>
void main()
{
int a[50];
int i,n,j,k,x,temp;
clrscr();
printf("Enter the number of elements you want to enter");
scanf("%d",&n);
for(i=0;i<n;i++)
{
printf("a[%d] =",i);
scanf(" %d",&a[i]);
}

for(j=0;j<n-1;j++)
 {
 for(k=0;k<n-j-1;k++)
  {
   if(a[k]>a[k+1])
    {
     temp=a[k];
     a[k]=a[k+1];
     a[k+1]=temp;
    }
   }
  }

 printf("\n\nSORTED ARRAY IS:\n\n");
 for(x=0;x<n;x++)
 {
 printf("\na[%d] = %d",x,a[x]);
 }
getch();
}

Selection Sort

#include<stdio.h>
#include<conio.h>
void main()
{
int a[50];
int i,n,j,k,x,temp;
printf("Enter the number of elements you want to enter");
scanf("%d",&n);
for(i=0;i<n;i++)
{
printf("a[%d] =",i);
scanf(" %d",&a[i]);
}

for(j=0;j<n-1;j++)
 {
 for(k=j+1;k<n;k++)
  {
  if(a[j]>a[k])
   {
   temp=a[j];
   a[j]=a[k];
   a[k]=temp;
   }
  }
 }
 printf("\n\nSORTED ARRAY IS:\n\n");
 for(x=0;x<n;x++)
 {
 printf("\na[%d] = %d",x,a[x]);
 }
getch();
}

Insert an element at desired position in array

#include<stdio.h>
#include<conio.h>
void main()
{
 clrscr();
 int a[10]={22,33,44,55,77,88};
 int i,j,k,n,t,x,z=0;
 printf("The elements of array are");
 for(i=0;i<=5;i++)
 {
   printf("\na[%d]= %d",i,a[i]);
 }
 printf("\nenter the location where you want to insert the element in the array");
 scanf("%d",&k);

 for(j=i-1;j>=k;j--)
  {
   a[j+1]=a[j];
   printf("\nNow a[%d] contains %d",j+1,a[j]);
  }
 printf("\nNow a[%d] contains %d",j+1,z);

 for(j=k-1;j>=0;j--)
 {
  printf("\nNow a[%d] contains %d",j,a[j]);
 }
 printf("enter the element to be inserted into the array");
 scanf("%d",&n);
 a[k]=n;
 t=i+1;
 printf("\n\nNew array after insertion is\n\n");
 for(i=0;i<t;i++)
  {
  printf("\nNow a[%d] contains %d",i,a[i]);
 }
 getch();
}

Insertion of an element at last of array

#include<stdio.h>
#include<conio.h>
void main()
{
int a[10]={1,2,3,4,5};
int n;
printf("\nAt present elements of array are");
for(int i=0;i<=4;i++)
{
printf("\n%d",a[i]);
}
printf("\nEnter the element you want to insert");
scanf("%d",&n);
a[i]=n;
printf("\n New array after insertion is");
for(i=0;i<=5;i++)
{
printf("\n%d",a[i]);
}
getch();
}

Calculate number of students having marks more than 60

#include<stdio.h>
#include<conio.h>
void main()
{
int marks[10],i,n=0,m;
clrscr();
printf("CALCULATE NUMBER OF STUDENTS HAVING MARKS >60");

for(i=0;i<=9;i++)
{
printf("\nEnter marks of student number %d",i+1);
scanf("%d",&marks[i]);
}
for(i=0;i<=9;i++)
{
if(marks[i]>60)
{
n++;
}
}
printf("\nNumber of students having marks more than 60 are : %d",n);
getch();
}

Accessing array elements using base address

#include<stdio.h>
#include<conio.h>
void main()
{
int data[5]={1,2,3,4,5};
int i;
int *base_add;
base_add=data;
clrscr();
printf("\t ACCESSING ARRAY ELEMENT USING BASE ADDRESS\N");
printf("\nHere base address is %u",base_add);
for(i=0;i<=4;i++)
{
printf("\nAt address= %u",base_add);
printf("\nWe have data[%d] i.e %d",i,*base_add);
base_add++;
}
getch();
}

Traversing an Array

Traversing an array means to access each and very element of array .It can be accessed using for loops.The data stored in array can be travesred by using for loop and the elements can be accessed by incerement the for loop. The loop starts to traverse array from the start of the array and continue to traverse array until the for lopp continues its execution until the for loop ends.UIn the program below the elements are stored in an array and are travesred using for loop . The loop prints all the elements of array using traversing.

 

Program for traversing an array.

#include<iostream.h>

#include<conio.h>

void main()

{

int data[5]={1,2,3,4,5};

int i;

clrscr();

cout<<""Elements of array Data are";

for(i=0;i<=4;i++)

{

cout<<data[i];

}

getch();

}

 

Find average of two numbers

#include<iostream.h>
#include<conio.h>
void main()
{
float a,b,average;
cout<<"Enter two numbers";
cin>>a>>b;
average=(a+b)/2;
cout<<"\n Average of two numbers is"<<average;
getch();
}

A simple "Hello World" program

#include<iostream.h>  //Header file
#include<conio.h>
void main()                // main function
{
cout<<"Hello World";
getch();
}



See also:
Find average of two numbers

                                          

Swapping value of two variables without third variable

#include<iostream.h>
#include<conio.h>
void main()
{
int a,b;
cout<<"enter the value of a";
cin>>a;
cout<<"\n Enter b";
cin>>b;  
a=a+b;  
b=a+b;  

a=b-a;    
b=-1*(a-b)-a;

cout<<"\n a is"<<a;
cout<<"\n b is"<<b;
getch();
}