Programming Examples - Arrays | Learn to Program with C++: Beginner to Expert - Back-End Programming PDF Download

Example 1: Sort an Array Elements in Ascending Order in C++
Sort an array elements means arrange elements of array in Ascending Order and Descending Order. You can easily sort all elements using bubble sort.
Program 1: C++ Program to Sort Elements of Array in Ascending Order

#include<iostream.h>
#include<conio.h>
void main()
{
int i,a[10],temp,j;
clrscr();
cout<<"Enter any 10 num in array: \n";
for(i=0;i<=10;i++)
{
cin>>a[i];
}
cout<<"\nData before sorting: ";
for(j=0;j<10;j++)
{
cout<<a[j];
}
for(i=0;i<=10;i++)
{
for(j=0;j<=10-i;j++)
{
if(a[j]>a[j+1])
{
temp=a[j];

a[j]=a[j+1];
a[j+1]=temp;
}
}
}
cout<<"\nData after sorting: ";
for(j=0;j<10;j++)
{
cout<<a[j];
}
getch();
}
Output
Enter any 10 num in array:
2 5 1 7 5 3 8 9 11 4
Data After Sorting: 1 2 3 4 5 7 8 9 11

Program 2: C++ Program to Sort an Array Elements in Descending Order.
For Sort Elements of Array in Descending Order we print all Elements of array from last index to first. For example arr[10], arr[9], arr[8],....arr[0]
Example

#include<iostream.h>
#include<conio.h>
void main()
{
int i,a[10],temp,j;
clrscr();
cout<<"Enter any 10 num in array : \n";
for(i=0;i<=10;i++)
{
cin>>a[i];
}
cout<<"\n\nData before sorting: ";
for(j=0;j<10;j++)
{
cout<<a[j];
}
for(i=0;i<=10;i++)
{
for(j=0;j<=10-i;j++)
{
if(a[j]>a[j+1])
{
temp=a[j];
a[j]=a[j+1];
a[j+1]=temp;
}
}
}
cout<<"\nData after sorting: ";
for(j=9;j>=0 ;j--)
{
cout<<a[j];
}
getch();}
Output
Enter any 10 num in array:
2 5 1 7 5 3 8 9 11 4
Data After Sorting: 11 9 8 7 5 4 3 2 1

Example 2: Sort an Array Elements in Ascending Order in C++
Sort an array elements means arrange elements of array in Ascending Order and Descending Order. You can easily sort all elements using bubble sort.
Sort Array Elements in Ascending order means arrange elements of array in Increasing Order.
To understand below Example, you have must knowledge of following C++ programming topics; For Loop in C++ and Swap Program in C++.
Process of Sorting an Array
The process of sorting an array requires the exchanging of Array values. While this seems to be a simple process, a computer must be careful that no values are lost during this exchange.
Suppose that Marks[1] = 60 and Marks[2] = 80 and you want to exchange their values so that Marks[1] = 80 and Marks[2] = 60. So you could NOT just do this
Example

Marks[1] = Marks[2];
Marks[2] = Marks[1];  // NOT WORK! Both Marks[1] and Marks[2] Store 80

In the first step, the value stored in Marks[1] is erased and replaced with Marks[2]. The result is that both Marks[1] and Marks[2] now have the same value. Oops! Then what happened to the value in Marks[1]? It is lost!!!
In order to swap two values, you must use a third variable, (a "temporary holding variable"), to temporarily hold the value you do not want to lose:
Example

temp = Marks[1];     // holding variable
Marks[1] = Marks[2];
Marks[2] = temp;

This process successfully exchanges, "swaps", the values of the two variables (without the loss of any values).
Different Ways to Sort Array Elements
There are literally hundreds of different ways to sort arrays. The basic goal of each of these methods is the same: to compare each array element to another array element and swap them if they are in the wrong position.

• Bubble Sort
• Exchange Sort
• Selection Sort
• Insertion Sort
• Shell Sort
• Quick Sort
• Merge Sort

In Below code we sort array Elements in Ascending Order Using Bubble sort (Bubble Sort Program in C++). Bubble sort is based on the idea of repeatedly comparing pairs of adjacent elements and then swapping their positions if they exist in the wrong order.
Program: C++ Program to Sort Elements of Array in Ascending Order

#include<iostream.h>
#include<conio.h>
void main()
{
int i,a[10],temp,j;
clrscr();
cout<<"Enter any 10 num in array: \n";
for(i=0;i<=10;i++)
{
cin>>a[i];
}
cout<<"\nData before sorting: ";
for(j=0;j<10;j++)
{
cout<<a[j];
}
for(i=0;i<=10;i++)
{
for(j=0;j<=10-i;j++)
{
if(a[j]>a[j+1])
{
temp=a[j];
a[j]=a[j+1];
a[j+1]=temp;
}
}
}
cout<<"\nData after sorting: ";
for(j=0;j<10;j++)
{
cout<<a[j];
}
getch();
}
Output
Enter any 10 num in array:
2 5 1 7 5 3 8 9 11 4
Data After Sorting: 1 2 3 4 5 7 8 9 11

Example 3: Sort an Array Elements in Descending Order in C++
Sort Array Elements in descending order means arrange elements of array in decreasing Order. You can easily sort all elements using Bubble Sort in C++.
To understand below Example, you have must knowledge of following C++ programming topics; For Loop in C++ and Swap Program in C++.
For Sort Elements of Array in Descending Order we print all Elements of array from last index to first. For example arr[10], arr[9], arr[8],....arr[0]
Program 1: Sort an Array Elements in Descending Order in C++

#include<iostream.h>
#include<conio.h>
void main()
{
int i,a[10],temp,j;
clrscr();
cout<<"Enter any 10 num in array : \n";
for(i=0;i<=10;i++)
{
cin>>a[i];
}
cout<<"\n\nData before sorting: ";
for(j=0;j<10;j++)
{
cout<<a[j];
}

for(i=0;i<=10;i++)
{
for(j=0;j<=10-i;j++)
{
if(a[j]>a[j+1])
{
temp=a[j];
a[j]=a[j+1];
a[j+1]=temp;

}
}
}
cout<<"\nData after sorting: ";
for(j=9;j>=0 ;j--)
{
cout<<a[j];
}
getch();
}
Output
Enter any 10 num in array:
2 5 1 7 5 3 8 9 11 4
Data After Sorting: 11 9 8 7 5 4 3 2 1

Example 4: Addition of Two Matrix Program in C++
To achieve Addition of two matrix we need two dimensional array and add their elements with each other and print result on screen.
Program: Addition of Two Matrix Program in C++

#include<iostream.h>
#include<conio.h>
void main()
{
int x[3][3],y[3][3],z[3][3],i,j;
clrscr();
cout<<"ENTER ELEMENTS OF 1st MATRIX\n";
for(i=0;i<3;i++)
{
for(j=0;j<3;j++)
cin>>x[i][j];
}
cout<<"ENTER ELEMENTS OF 2nd MATRIX\n";
for(i=0;i<3;i++)
{
for(j=0;j<3;j++)
cin>>y[i][j];
}
cout<<"MATRIX [X]";
for(i=0;i<3;i++)
{
cout<<"\n\n";
for(j=0;j<3;j++)
cout<<x[i][j];
}
cout<<"\nMATRIX [Y]";
for(i=0;i<3;i++)
{
cout<<"\n\n";
for(j=0;j<3;j++)
cout<<y[i][j];
}
for(i=0;i<3;i++)
{
for(j=0;j<3;j++)
z[i][j]=x[i][j]+y[i][j];
}
cout<<"\nMATRIX [Z]";
for(i=0;i<3;i++)
{
cout<<"\n\n";
for(j=0;j<3;j++)
cout<<z[i][j];
}
getch();
}

Output
ENTER ELEMENTS OF 1^st MATRIX
1
2
3
4
5
6
7
8
9
ENTER ELEMENTS OF 2^nd MATRIX
4
5
6
3
2
1
7
9
5
MATRIX [X]
1 2 3
4 5 6
7 8 9
MATRIX [Y]
4 5 6
3 2 1
7 9 5
MATRIX [Z]
5 7 9
7 7 7
14 17 14

Example 5: C++ Program to Find Sum of Diagonal Elements of Matrix
Using this code we find the sum of diagonal elements of a square matrix.For example, for a 2 x 2 matrix, the sum of diagonal elements of the matrix {1,2,3,4} will be equal to 5.
To write this code is same as the sum of elements of a matrix, we add only those elements of the matrix for which row number and column number is same, like 1st row and 1st column, 2nd row and 2nd column and so on(i==j).
Example

1    2
3    4
Sum = 1+4 = 5

Considering 3 x 3 matrix

• We have to add a[0][0],a[1][1],a[2][2]
• By Observing, it is clear that when i = j Condition is true then and then only we have to add the elements

Diagonal Matrix

Program : C++ Program to Find Sum of Diagonal Elements of Matrix

#include<stdio.h>
#include<conio.h>
void main()
{
int i, j, matrix[10][10], row, col;
int sum = 0;
clrscr();
cout<<"\nEnter the number of Rows : ";
cin>>row;
cout<<"\nEnter the number of Columns : ";
cin>>col;
//Accept the Elements in m x n Matrix
for (i = 0; i < row; i++)
{
for (j = 0; j < col; j++)
{
cout<<"\nEnter the Element a[%d][%d] : ", i, j;
cin>>matrix[i][j];
}
}
//Addition of all Diagonal Elements
for (i = 0; i < row; i++)
{
for (j = 0; j < col; j++)
{
if (i == j)
sum = sum + matrix[i][j];
}
}
//Print out the Result
cout<<"\nAddition of Diagonal Array Elements in the Matrix is: "<<sum;
getch();
}
Output
Enter the number of Rows : 2
Enter the number of Columns : 2
Enter the Element a[0][0] : 1
Enter the Element a[0][1] : 2
Enter the Element a[1][0] : 3
Enter the Element a[1][1] : 4
Addition of Diagonal Array Elements in the Matrix is: 5

Example 6: C++ Program to Multiply Two Matrices
A matrix is a rectangular array of numbers that is arranged in the form of rows and columns. A 2*2 matrix has 2 rows and 2 columns, A 3*3 matrix has 3 rows and 3 columns.
To write matrices program in C++ we need receive two matrices value from user after this process we start multiplying the two matrices and store the multiplication result inside any variable and finally store the value of sum in the third matrix say mat3[ ][ ].
To understand below example, you have must knowledge of following C++ programming topics; For Loop in C++ and Array in C++.
Examples to C++ Program to Multiply Two Matrices
The below program multiplies two square matrices of size 4*4
Example

Input : Matrices_1[][] = {{1, 2},
{3, 4}}
Matrices_2[][] = {{1, 1},
{1, 1}}
Output : {{3, 3},
{7, 7}}
Input : Matrices_1[][] = {{2, 4},
{3, 4}}
Matrices_2[][] = {{1, 2},
{1, 3}}
Output : {{6, 16},
{7, 18}}

To understand below example, you have must knowledge of following C++ programming topics; String in C++, for looping statements we need know For Loop in C++ and Array in C++.
Program 1: Program to Multiply 2X2 Matrices in C++

#include<iostream.h>
#include<conio.h>
void main()
{
clrscr();
int mat1[2][2], mat2[2][2], mat3[2][2], sum=0, i, j, k;
cout<<"Enter First Matrix Element (2*2): ";
for(i=0; i<2; i++)
{
for(j=0; j<2; j++)
{
cin>>mat1[i][j];
}
}
cout<<"Enter Second Matrix Element (2*2): ";
for(i=0; i<2; i++)
{
for(j=0; j<2; j++)
{
cin>>mat2[i][j];
}
}
cout<<"Multiplying two Matrices........\n";
for(i=0; i<2; i++)
{
for(j=0; j<2; j++)
{
sum=0;
for(k=0; k<2; k++)
{
sum = sum + mat1[i][k] * mat2[k][j];
}
mat3[i][j] = sum;
}
}
cout<<"\nMultiplication of Two Matrices : \n";
for(i=0; i<2; i++)
{
for(j=0; j<2; j++)
{
cout<<mat3[i][j]<<" ";
}
cout<<"\n";
}
getch();
}

Output
Enter First Matrix Element (2*2): 2
3
4
1
Enter Second Matrix Element (2*2): 7
4
3
5
Multiplying two Matrices........
Multiplication of Two Matrices
23 23
31 21

Program 2: Program to Multiply 3 x 3 Matrices in C++

#include<iostream.h>
#include<conio.h>
void main()
{
clrscr();
int mat1[3][3], mat2[3][3], mat3[3][3], sum=0, i, j, k;
cout<<"Enter First Matrix Element (3*3): ";
for(i=0; i<3; i++)
{
for(j=0; j<3; j++)
{
cin>>mat1[i][j];
}
}
cout<<"Enter Second Matrix Element (3*3): ";
for(i=0; i<3; i++)
{
for(j=0; j<3; j++)
{
cin>>mat2[i][j];
}
}
cout<<"Multiplying two Matrices........\n";
for(i=0; i<3; i++)
{
for(j=0; j<3; j++)
{
sum=0;
for(k=0; k<3; k++)
{
sum = sum + mat1[i][k] * mat2[k][j];
}
mat3[i][j] = sum;
}
}
cout<<"\nMultiplication of Two Matrices : \n";
for(i=0; i<3; i++)
{
for(j=0; j<3; j++)
{
cout<<mat3[i][j]<<" ";
}
cout<<"\n";
}
getch();
}
Output
Enter First Matrix Element (3*3): 3
2
1
4
3
5
6
3
2
Enter Second Matrix Element (3*3): 3
2
4
5
2
1
6
7
3
Multiplying two Matrices........
Multiplication of Two Matrices
25 17 17
57 49 34
45 32 33

Example 7: C++ Program to Transpose Matrix
To transpose any matrix in C++ Programming language, you have to first ask to the user to enter the matrix and replace row by column and column by row to transpose that matrix, then display the transpose of the matrix on the screen as shown here in the following C++ program.
Examples to C++ Program to Transpose Matrix
The transpose of this matrix is shown below: Rows and columns are interchanged, rows of original matrix becomes column in transpose and columns of original matrix becomes rows in transpose.
Example

----------------

| 1  | 2  | 3  |

| 4  | 5  | 6  |

| 7  | 8  | 9  |

| 10 | 11 | 12 |

----------------

Example

---------------------

| 1  | 4  | 7  | 10 |

| 2  | 5  | 8  | 11 |

| 3  | 6  | 9  | 12 |

---------------------

To understand below example, you have must knowledge of following C++ programming topics; String in C++, for looping statements we need know For Loop in C++ and Array in C++.
Program: C++ Program to Transpose Matrix

#include<iostream.h>
#include<conio.h>
void main()
{
int matrix[5][5],transpose_matrix[5][5];
int i,j,rows,cols;
clrscr();
// Taking Input In Array
cout<<"Enter Number of Rows: ";
cin>>rows;
cout<<"Enter Number Of Columns: ";
cin>>cols;
for( i=0;i<rows;i++){
for( j=0;j<cols;j++)
{
cin>>matrix[i][j];
}
}
cout<<"\n Matrix You Entered\n";
for( i=0;i<rows;i++){
for( j=0;j<cols;j++)
{
cout<<matrix[i][j]<<"     ";
}
cout<<endl;
}
// Calculating Transpose of Matrix
cout<<"\n\n\nTranspose of Entered Matrix\n";
for( i=0;i<rows;i++){
for( j=0;j<cols;j++)
{
transpose_matrix[j][i]=matrix[i][j];
}
cout<<endl;
}
//Displaying Final Resultant Array
for( i=0;i<cols;i++){
for( j=0;j<rows;j++)
{
cout<<transpose_matrix[i][j]<<"    ";
}
cout<<endl;
}
getch();}
Output
Enter Number of Rows: 2
Enter Number Of Columns: 3
4
5
6
7
1
2
Matrix You Entered
4  5  6
7  1  2
Transpose of Entered Matrix
4  7
5  1
6  2

Example 8: C++ Program to Pass Array in Function
In below program we pass array in function as an arguments and finally print all elements of an array.
Example

#include<iostream.h>
#include<conio.h>
void pass(int[],int);
void main()
{
int a[]={1,2,3,4,5};
clrscr();
pass(a,5);
getch();
}
void pass(int b[],int n)
{
int i;
for(i=0;i<n;i++)
{
cout<<"/n"<<b[i];
}
}
Output
1
2
3
4
5

Example 9: C++ Program to Find Average of Numbers Using Arrays
Average of numbers is calculated by adding all the numbers and then dividing the sum by count of numbers available.
In below code we receive integer input from user and storing it in array. Then we will find the sum of all array elements using for loop and finally calculate the average of N input numbers stored in an array.
To understand this code you need basic knowledge about Array in C++ and For Loop in C++.
Example

The numbers whose average is to be calculated are:
10, 20, 30, 40, 50
Sum of numbers = 150
Average of numbers = 150/5 = 30

Program: C++ Program to Find Average of Numbers Using Arrays

#include<iostream.h>
#include<conio.h>
void main()
{
int i, count, sum, inputArray[500];
float average;
clrscr();
cout<<"Enter number of Elements: ";
cin >> count;
cout<<"Enter " << count << " any Elements in Array:\n";
for(i = 0; i < count; i++) {
cin >> inputArray[i];
}
sum = 0;
// Find sum of all array elements
for(i = 0; i < count; i++) {
sum += inputArray[i];
}
average = (float)sum / count;
cout << "Average: " << average;
getch();
}
Output
Enter number of Elements: 5
Enter any Elements in Array:
20
40
30
50
10
Average: 30

Example 10: C++ Program to Merge two Arrays in third array
In this program we enter an elements in any two array and then these two array (elements of array) are store in third array.
Example

#include<iostream.h>
#include<conio.h>
void main()
{
int a[10],b[10],c[20],i;
clrscr();
cout<<"Enter Elements in 1st Array: ";
for(i=0;i<10;i++)
{
cin>>a[i];
}
cout<<"Enter Elements in 2nd Array: ";
for(i=0;i<10;i++)
{
cin>>b[i];
}
cout<<"\nElements of Array After Merge: ";
for(i=0;i<10;i++)
{
c[i]=a[i];
c[i+10]=b[i];
}
for(i=0;i<20;i++)
{
cout<<c[i];
}
getch();
}

Output
ENTER ELEMENT IN 1^ST ARRAY 11
2
3
4
5
6
7
8
9
10
ENTER ELEMENT IN 1^ST ARRAY 2
3
4
5
6
7
8
9
2
1
ELEMENT OF 1^ST ARRAY 11 2 3 4 5 6 7 8 9 10
ELEMENT o f 2^ND ARRAY 2 3 4 5 6 7 8 9 2 1
ELEMENT OF ARRAY AFTER MERGE 11 2 3 4 5 6 7 8 9 1 0 2 3 4 5 6 7 8 9 2 1

Example 11: C++ program to Insert an element in an array at specific position
Insert an element in an array at specific position on the basis of index value.
Example

#include<iostream.h>
#include<conio.h>
void main()
{
int i,a[5],no,pos;
clrscr();
cout<<"Enter data in Array: ";
for(i=0;i<5;i++)
{
cin>>a[i];
}
cout<<"\n\nStored Data in Array: ";
for(i=0;i<5;i++)
{
cout<<a[i];
}
cout<<"\n\nEnter position to insert number: ";
cin>>pos;
if(pos>5)
{
cout<<"\n\nThis is out of range";
}
else
{
cout<<"\n\nEnter new number: ";
cin>>no;
--pos;
for(i=5;i>=pos;i--)
{
a[i+1]=a[i];
}
a[pos]=no;
cout<<"\n\nNew data in Array: ";
for(i=0;i<6;i++)
{
cout<<a[i];
}
}
getch();
}

Output
Enter data in Array :
10
20
30
40
50
60
Stored data in Array : 10 20 40 50 60
Enter position to insort number : 30
Enter new Number : 8New data in Array : 10 20 30 40 50 60

Example 12: Search an Array Elements Program in C++
For search array element you need to compare all array element with that particular elements. In below C++ program we have to search an element in a given array using linear search algorithm. If given element is present in array then we will print it's index otherwise print a message saying element not found in array.
To understand this code you need basic knowledge about Array in C++ and For Loop in C++.
Linear Search in C++
In linear search algorithm, we compare targeted element with each element of the array. If the element is found then its position is displayed. The worst case time complexity for linear search is O(n).
Example

Input Array : [6, 12, 9, 8, 31, 10, 25]
Element to search : 31
Output :
Element found at index 4

Program: Search Array Elements Program in C

#include<iostream.h>
#include<conio.h>
void main()
{
int i,a[50],num,size;
clrscr();
cout<<"Enter size of array: ";
cin>>size;
cout<<"Enter any"<<size <<"element in array: \n";
for(i=0; i<size; i++)
{
cin>>a[i];
}
cout<<"Enter number for find their position: ";
cin>>num;
for(i=0; i<size; i++)
{
if(a[i]==num)
{
cout<<"\n index of "<<num <<" is " <<i;
}
}
getch();
}
Output
Enter size of array: 5
Enter any 5 elements in array:
20
40
30
50
10
Enter number for find their position: 50
index of 50 is 3

Note: Here we print number inxed value. That's why actual position of number is less than 1.

Example 13: C++ Program to Delete an element from Array
Program: Delete an element in an array from specific position

#include<iostream.h>
#include<conio.h>
void main()
{
int i,a[5],no,pos;
clrscr();
cout<<"Enter Data in Array: ";
for(i=0;i<5;i++)
{
cin>>a[i];
}
cout<<"\n\nStored Data in Array:  ";
for(i=0;i<5;i++)
{
cout<<a[i];
}
cout<<"\n\nEnter poss. of Element to Delete: ";
cin>>pos;
if(pos>5)
{
cout<<"\n\nThis value is out of range: ";
}
else
{
--pos;
for(i=pos;i<=4;i++)
{
a[i]=a[i+1];
}
cout<<"\n\nNew Data in Array: ";
for(i=0;i<4;i++)
{
cout<<a[i];
}
}
getch();
}
Output
Enter Data in Array: 10 20 30 40 50
Stored Data in Array: 10 20 30 40 50
Enter poss. of Element to Delete: 2
New data in Array: 10 20 40 50

Example 14: C++ Program to Find Even and Odd Elements in Array
For Separate Even and Odd Elements of Array we take three array and one array for insert all Array Elements second for even elements and third for odd elements. We check condition for odd and even Elements arr[]%2==0.
Example

#include<iostream.h>
#include<conio.h>
void main()
{
int arr[20],even[20],odd[20],i,j=0,k=0,no;
clrscr();
cout<<"How Size of Array: ";
cin>>no;
cout<<"Enter any "<<no<<" elements in Array: ";
for(i=0; i<no;i++)
{
cin>>arr[i];
}
for(i=0; i<no;i++)
{
if(arr[i]%2==0)
{
even[j]=arr[i];
j++;
}
else
{
odd[k]=arr[i];
k++;
}
}
cout<<"\nEven Elements: ";
for(i=0; i<j ;i++)
{
cout<<even[i]<<"  ";
}
cout<<"\nOdd Elements: ";
for(i=0; i<k; i++)
{
cout<<odd[i]<<"  ";
}
getch();
}
Output
Enter Size of Array : 5
Enter any 5 elements in Array:
10 4 5 2 7
Even Elements: 10 4 2
Odd Elements: 7 5

Example 15: C++ Program to Reverse an Array
Array store all data in array on the basis of index. For reverse an array element you nedd to interchange elements of array on the basis of index value.
Program: C++ Program to Reverse an Array

#include<iostream.h>
#include<conio.h>
void main()
{
int a[20],b[20],i,j,n;
clrscr();
cout<<"How many elements you want to enter: ";
cin>>n;
cout<<"Enter any "<<n<<" elements in Array: ";
for(i=0; i<n ;i++)
{
cin>>a[i];
}
cout<<"Reverse of Array: ";
for(i=n-1,j=0; i>=0;i--,j++)
{
b[i]=a[j];
}
for(i=0; i<n ;i++)
{
cout<<b[i];
}
getch();
}
Output
How many elements you want to enter : 5
Enter any 5 elements in Array:
1 4 2 7 5
Reverse of Array: 5 7 2 4 1