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Sum of n numbers in C

Sum of n numbers in C: This program adds n numbers which will be entered by a user. The user will enter a number indicating how many numbers to add and then the user will enter n numbers. To perform the arithmetic operation of addition of n numbers we can use an array or do it without using an array.

C program to sum n numbers using a for loop

  1. #include <stdio.h>
  2.  
  3. int main()
  4. {
  5.   int n, sum = 0, c, value;
  6.  
  7.   printf("How many numbers you want to add?\n");
  8.   scanf("%d", &n);
  9.  
  10.   printf("Enter %d integers\n", n);
  11.  
  12.   for (c = 1; c <= n; c++)
  13.   {
  14.     scanf("%d", &value);
  15.     sum = sum + value;
  16.   }
  17.  
  18.   printf("Sum of the integers = %d\n", sum);
  19.  
  20.   return 0;
  21. }

You can use long int or long long data type for the variable sum.
Download Add n numbers program.

Output of program:
Add n numbers C program output

C program to calculate sum of n numbers using an array

  1. #include <stdio.h>
  2.  
  3. int main()
  4. {
  5.    int n, sum = 0, c, array[100];
  6.  
  7.    scanf("%d", &n);
  8.  
  9.    for (c = 0; c < n; c++)
  10.    {
  11.       scanf("%d", &array[c]);
  12.       sum = sum + array[c];
  13.    }
  14.  
  15.    printf("Sum = %d\n", sum);
  16.  
  17.    return 0;
  18. }

The advantage of using an array is that we have a record of the numbers entered by a user and can use them further in the program if required but storing numbers will require additional memory.

C program for addition of n numbers using recursion

  1. #include <stdio.h>
  2.  
  3. long calculate_sum(int [], int);
  4.  
  5. int main()
  6. {
  7.   int n, c, array[100];
  8.   long result;
  9.  
  10.   scanf("%d", &n);
  11.  
  12.   for (c = 0; c < n; c++)
  13.     scanf("%d", &array[c]);
  14.  
  15.   result = calculate_sum(array, n);
  16.  
  17.   printf("Sum = %ld\n", result);
  18.  
  19.   return 0;
  20. }
  21.  
  22. long calculate_sum(int a[], int n) {
  23.   static long sum = 0;
  24.  
  25.   if (n == 0)
  26.     return sum;
  27.  
  28.   sum = sum + a[n-1];
  29.  
  30.   return calculate_sum(a, --n);
  31. }