C Exercises: Find the sum of all elements of an array

Last update on March 18 2025 13:23:59 (UTC/GMT +8 hours)

3. Array Sum Calculation

Write a program in C to find the sum of all elements of an array.

The task requires writing a C program to read a specified number of integers into an array and then calculate and print the sum of these elements. After storing the input values, the program should iterate through the array to compute the total sum and display the result.

Visual Presentation:

C Exercises: Find the sum of all elements of an array

Sample Solution:

#include <stdio.h>
// Main function
int main()
{
    int a[100];  // Declare an array of size 100 to store integer values
    int i, n, sum = 0;  // Declare variables to store array size, loop counter, and sum
    // Display a message to the user about the program's purpose
    printf("\n\nFind sum of all elements of array:\n");
    printf("--------------------------------------\n");	
    // Prompt the user to input the number of elements to be stored in the array
    printf("Input the number of elements to be stored in the array :");
    scanf("%d", &n);
    // Prompt the user to input n elements into the array
    printf("Input %d elements in the array :\n", n);
    for (i = 0; i < n; i++)
    {
        printf("element - %d : ", i);
        scanf("%d", &a[i]);  // Read the input and store it in the array
    }

    // Calculate the sum of all elements in the array using a for loop
    for (i = 0; i < n; i++)
    {
        sum += a[i];  // Add each element to the sum
    }
    // Display the sum of all elements stored in the array
    printf("Sum of all elements stored in the array is : %d\n\n", sum);
	return 0;
}

Sample Output:

Find sum of all elements of array:                                                                            
--------------------------------------                                                                        
Input the number of elements to be stored in the array :3                                                     
Input 3 elements in the array :                                                                               
element - 0 : 2                                                                                               
element - 1 : 5                                                                                               
element - 2 : 8                                                                                               
Sum of all elements stored in the array is : 15

Explanation:

  printf("Input the number of elements to be stored in the array :");
       scanf("%d",&n);
   
       printf("Input %d elements in the array :\n",n);
       for(i=0;i<n;i++)
        {
	      printf("element - %d : ",i);
	      scanf("%d",&a[i]);
	    }

    for(i=0; i<n; i++)
    {
        sum += a[i];
    }

    printf("Sum of all elements stored in the array is : %d\n\n", sum);

In the above code -

The first printf statement prompts the user to input the number of elements they want to store in the array and stores it in the variable n using scanf.
The second printf statement asks the user to input n number of elements into the array using a for loop, and stores each input in the corresponding index of the array a[i].
The third for loop calculates the sum of all the elements in the array by iterating over each element of the array and adding its value to the variable sum.
The final printf statement then prints out the sum of all the elements in the array using the value stored in the variable sum.

Flowchart :

For more Practice: Solve these Related Problems:

Write a C program to compute the sum of array elements using recursion instead of a loop.
Write a C program to calculate the sum of even-indexed elements in an array.
Write a C program to find the sum of array elements using pointer arithmetic without an index variable.
Write a C program to input an array and then compute both the sum and the product of its elements.

C Programming Code Editor:

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