List of C,C++ Programs on one Dimensional Arrays for Beginners

This is a collection of c, c++ programs on one dimensional arrays. Beginner students of c, c++ will find them useful.

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Parveen,

Program 1: Fill and display the elements of an array

The following program asks the user to enter the elements one by one and then displays them back to the console.

#include <iostream>
using namespace std;

int main()
{

  // array of 5 elements 
  const int SIZE = 5;

  // declare an int array 
  int arr [SIZE];

  // fill the array 
  for (int i = 0; i < SIZE; i++)
  {

    printf("Enter arr[%d]: ", i);

    cin >> arr[i];

  }

  // display the elements 
  for (int i = 0; i < SIZE; i++)
  {

    printf("arr[%d] = %d", i, arr [i]);

    printf("\r\n======\r\n");

  }

  return 0;

}

Output of the program is as follows:

Enter arr[0]: 4
Enter arr[1]: -1
Enter arr[2]: 6
Enter arr[3]: 8
Enter arr[4]: 2
arr[0] = 4
======
arr[1] = -1
======
arr[2] = 6
======
arr[3] = 8
======
arr[4] = 2
======

Program 2: Sum of the elements of an array

The following program creates a variable called sum. Then it adds the elements into sum, and displays it back to the console.

#include <iostream>
using namespace std;

int main()
{

  // array of 5 elements 
  const int SIZE = 5;

  // declare an int array 
  int arr[SIZE];

  // fill the array 
  for (int i = 0; i < SIZE; i++)
  {

    printf("Enter arr[%d]: ", i);

    cin >> arr[i];

  }

  // variable to store the sum 
  int sum = 0;

  for (int i = 0; i < SIZE; i++)
  {

    // aggregate 
    sum += arr[i];

  }

  printf("sum = %d", sum);

  return 0;

}

Output of the program is as follows:

Enter arr[0]: 9
Enter arr[1]: -1
Enter arr[2]: -9
Enter arr[3]: 2
Enter arr[4]: -2
sum = -1

Program 3: Search an element in an array

The following program compares the item to be searched with each element of the array. It prints the indices if the comparison succeeds, otherwise prints a regret message.

#include <iostream>
using namespace std;

int main()
{

  // array of 5 elements 
  const int SIZE = 5;

  // create an int array 
  int arr[SIZE] = { 8, 9, 7, -1, 0 };

  // element to search 
  int search;

  printf("Enter the element to search: ");

  cin >> search;

  // flag to tell us if 
  // found atleast once 
  bool found = false;

  for (int i = 0; i < SIZE; i++)
  {

    // compare with each element 
    if (search == arr[i])
    {

      printf("Found! at index %d", i);

      found = true;

    }

  }

  // regret, if not found 
  if (!found)
  {

    printf("Element not found.");

  }

  return 0;

}

Program 4: Find the largest element in an array

The following program starts by assuming the first element as the largest. Then it examines each element and updates the largest. Finally, it prints the largest.

#include <iostream>
using namespace std;

int main()
{

  // array of 5 elements 
  const int SIZE = 5;

  // create an int array 
  int arr[SIZE] = { 8, 9, 7, -1, 0 };

  // let first be the largest 
  int largest = arr[0];

  for (int i = 0; i < SIZE; i++)
  {

    // compare with each element 
    if (arr[i] > largest)
    {

      // and update the largest 
      largest = arr[i];

    }

  }

  printf("Largest = %d.", largest);

  return 0;

}

Program 5: Reverse an array

The following program reverses the array by swapping the first half with the second half.

#include <iostream>
using namespace std;

int main()
{

  // array of 5 elements 
  const int SIZE = 5;

  // create an int array 
  // pre-filled to keep the code 
  // easier to understand 
  int arr[SIZE] = { 8, 9, 7, -1, 0 };

  // swap the first part of the array 
  // with the latter part 
  for (int i = 0; i < SIZE/2; i++)
  {

    int temp = arr[i];

    arr[i] = arr[SIZE - i - 1];

    arr[SIZE - i - 1] = temp;

  }

  // print 
  for (int i = 0; i < SIZE; i++)
  {

    printf("arr[%d] = %d", i, arr[i]);

    printf("\n");

  }

  return 0;

}

Program 6:
Delete an element of an array and shift the remaining array

The following program obtains the index from the user and shifts the array backwards. Then it fills 0 to the last vacancy.

#include <iostream>
using namespace std;

int main()
{

  // array of 5 elements 
  const int SIZE = 5;

  // create or fill an array 
  int arr[SIZE] = { 8, 9, 7, -1, 4 };

  cout << "The array is: \n\n";

  // print the current array 
  for (int i = 0; i < SIZE; i++)
  {

    printf("arr[%d] = %d", i, arr[i]);

    printf("\n");

  }

  printf("\n");

  // at which index to delete 
  int del;

  printf("Index to delete?[0-4]: ");

  cin >> del;

  cout << "\n\n";

  // shift elements starting at 
  // the required index 
  for (int i = del; i < SIZE - 1; i++)
  {

    arr[i] = arr[i + 1];

  }

  // set last vacancy at, say, 0 
  arr[SIZE - 1] = 0;

  cout << "The array after removal ";

  cout << " at index " << del << " is: ";

  cout << "\n\n";

  // print 
  for (int i = 0; i < SIZE; i++)
  {

    printf("arr[%d] = %d", i, arr[i]);

    printf("\n");

  }

  return 0;

}

Output of the program is as follows:

The array is:
  arr[0] = 8
  arr[1] = 9
  arr[2] = 7
  arr[3] = -1
  arr[4] = 4
  Index to delete?[0-4]: 2
The array after removal  at index 2 is:
  arr[0] = 8
  arr[1] = 9
  arr[2] = -1
  arr[3] = 4
  arr[4] = 0

Program 7:
Insert an element into an array and shift the remaining array

The following program obtains the index from the user and shifts the array forward.

#include <iostream>
using namespace std;

int main()
{

  // large array of, say, 20 elements 
  const int SIZE = 20;

  // declare the arrat 
  int arr[SIZE];

  // the usable size of the array 
  int n;

  printf("Size of array?[< 20]: ");

  cin >> n;

  // fill the array 
  for (int i = 0; i < n; i++)
  {

    printf("Enter arr[%d]: ", i);

    cin >> arr[i];

  }

  // at what index to insert 
  printf("Insert at which index?: ");

  int ins;

  cin >> ins;

  printf("Which element?: ");

  int what;

  cin >> what;

  // shift the array forward 
  // starting at the required index 
  for (int i = n; i > ins; i--)
  {

    arr[i] = arr[i - 1];

  }

  // insert the number 
  arr[ins] = what;

  // print the elements 
  printf("\n\nArray now is: \n\n");

  for (int i = 0; i < n + 1; i++)
  {

    printf("arr[%d] = %d", i, arr[i]);

    printf("\n");

  }

  return 0;

}

Output of the program is as follows:

Size of array?[< 20]: 5
Enter arr[0]: 6
Enter arr[1]: 2
Enter arr[2]: 9
Enter arr[3]: 1
Enter arr[4]: 5
Insert at which index?: 2
Which element?: -4
Array now is:
  arr[0] = 6
  arr[1] = 2
  arr[2] = -4
  arr[3] = 9
  arr[4] = 1
  arr[5] = 5

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