Question

Write a program that finds (ANSWER IN C LANGUAGE!):

1. The sum of all elements at even subscripts
2. The sum of all elements at odd subscripts
3. The sum of all elements

You are allowed to perform this functionality within main.

Main program:
++++++++++++++++++++++++++++++++++++++++++++++++++++++++
#include <stdio.h>

int main()
{
/* Declare array variables */
const int NUM_VALS = 4;
int userValues[NUM_VALS];
int i; // counter
int even = 0;
int odd = 0;
int sum = 0;

/* Initialize the array with values */
userValues[0] = 2;
userValues[1] = 5;
userValues[2] = -1;
userValues[3] = 7;

return 0;
}
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======================
Sample Output:
======================
Sum of all elements at even subscripts = 1
Sum of all elements at odd subscipts = 12
Sum of all elements = 13

Answer 1

The code given below asks user to enter the number of values and then asks user to enter the values in the array.

In the code given below following steps are followed :

1. Calculate the sum of all the elements and store the answer in the sum variable.( for loop is used for this )

2. Calculate the sum of all the elements at even subscripts. To do this, modulus operator ( % ) is used to calculate the remainder after dividing subscript (index of array ) by 2 and if remainder is 0 then it is an even subscript. And so the sum of all the elements at even subscripts is calculated.

3. Sum of all the elements at odd subscripts is calculated by subtracting the sum of elements at even subscripts from the total sum of the elements .

odd = sum - even // here the sum variable stores the total sum of all the elements in the array.

/* Code starts from here */

#include <stdio.h>

int main()
{
    int NUM_VALS = 0; //variable to store the number of elements in the array.
    printf("Input:\n");
    printf("Enter the number of elements: ");
    scanf("%d",&NUM_VALS);
    int userValues[NUM_VALS]; //declaring array
    int i; // counter
  
    /*
    defining the variables to store the sum of all elements ,
    elements at even subscripts and elements at odd subscripts
    */
    int even = 0;
    int odd = 0;
    int sum = 0;

printf("Enter the values in the array: ");
for(i=0;i<NUM_VALS;i++)
{
    scanf("%d",&userValues[i]);
}

//calculating the sum of all elements
for(i=0;i<NUM_VALS;i++)
{
    sum += userValues[i];
}

//calculating the sum of all elements at even subscripts
for(i=0;i<NUM_VALS;i++)
{
    if((i%2)==0)
    {
        even = even + userValues[i];
    }
}
//calculating the sum of all elements at odd subscripts
odd = sum - even;

printf("\nOutput: \n");
printf("Sum of all elements at even subscripts = %d\n",even);
printf("Sum of all elements at odd subscripts = %d\n",odd);
printf("Sum of all elements = %d\n",sum);

    return 0;
}

/* Code ends here */

The code given below completes the code given in the question. It does not asks the user for the number of elements in the array. Number of elements in the array is initialized at the beginning and the elements in the array are also initialized .

It simply calculates the sum of all the elements , sum of elements at even subscripts and sum of elements at odd subscripts and prints the answer on the screen.

/* Code starts from here */

#include <stdio.h>

int main()
{

/* Declare array variables */
const int NUM_VALS = 4;
int userValues[NUM_VALS];
int i; // counter
int even = 0;
int odd = 0;
int sum = 0;

/* Initialize the array with values */
userValues[0] = 2;
userValues[1] = 5;
userValues[2] = -1;
userValues[3] = 7;
//calculating the sum of all elements
for(i=0;i<NUM_VALS;i++)
{
    sum += userValues[i];
}

//calculating the sum of all elements at even subscripts
for(i=0;i<NUM_VALS;i++)
{
    if((i%2)==0)
    {
        even = even + userValues[i];
    }
}
//calculating the sum of all elements at odd subscripts
odd = sum - even;

printf("\nOutput: \n");
printf("Sum of elements at even subscripts = %d\n",even);
printf("Sum of elements at odd subscripts = %d\n",odd);
printf("Sum of all elements = %d\n",sum);

    return 0;
}

/* Code ends here */

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