Question

Explain What is being executed in this code. State all changes in values when traversing loops.

#include <stdio.h>

#define NUM_PRODUCTS 2

#define NUM_CATEGORIES 2

#define NUM_DIGITS 2

struct ProductInfo

{

int prodID;

int numberInStock;

double unitPrice;

};

int main(void)

{

struct ProductInfo productList[NUM_PRODUCTS] =

{

{78, 8, 19.95},

{95, 14, 22.98}

};

int categoryCount[NUM_CATEGORIES] = { 0 };

int i, j, sum, id, divisors[] = { 10, 1 };

for (i = 0; i < NUM_PRODUCTS; i++)

{

sum = 1;

id = productList[i].prodID;

for (j = 0; j < 2; j++)

{

sum *= id / divisors[j];

id = id % divisors[j];

}

categoryCount[sum % NUM_CATEGORIES] += productList[i].numberInStock;

}

for (i = 0; i < NUM_CATEGORIES; i++)

{

if (categoryCount[i] % 2 == 0)

{

printf("Category %d has %d items\n", i, categoryCount[i]);

}

}

return 0;

}

Answer 1

The main purpose of thia code is to count the number of items in stock in that category and print them.

In this code three constants have been declared , each with a value of 2.

#define NUM_PRODUCTS 2

#define NUM_CATEGORIES 2

#define NUM_DIGITS 2

The structure is created named ProductInfo with variables prodID,numberInStock and unitPrice.

struct ProductInfo

{

int prodID;

int numberInStock;

double unitPrice;

};

Now in the main loop ,

We created two objects of the structure ProductInfo and provided values for the variables in that structure for each object using the code snippet:

struct ProductInfo productList[NUM_PRODUCTS] =

{

{78, 8, 19.95},

{95, 14, 22.98}

};

So there are now two objects of the structure ProductInfo they are ProductInfo[0] and ProductInfo{1] and

• productList[0].prodId = 78
• productList[0].numberInStock = 8
• productList[0].unitPrice = 78
• productList[1].prodId = 78
• productList[1].numberInStock = 8
• productList[1].unitPrice = 78

The required variables for the forloop execution and the output generation is declared using the code snippet:

int categoryCount[NUM_CATEGORIES] = { 0 };   //two valued array as NUM_CATEGORIES = 2

int i, j, sum, id, divisors[] = { 10, 1 };

Now the changes taking place in this for loop snippet is as follows:

for (i = 0; i < NUM_PRODUCTS; i++)
{
sum = 1;
id = productList[i].prodID;
for (j = 0; j < 2; j++)
{
sum *= id / divisors[j];
id = id % divisors[j];
}
categoryCount[sum % NUM_CATEGORIES] += productList[i].numberInStock;
}

At first loop the sum is declared as 1 and id = productList[0].prodID = 78.

Now it enters the j loop which executes two times.

In the first loop the values of variables are as follows:

• sum:7
• id:8

In the second loop the values of variables are as follows:

• sum:56
• id:0

And Category count[0]=8

Now in the second loop ,sum is declared as 1 and id = productList[1].prodID = 95

Now it enters the j loop which executes two times.

In the first loop the values of variables are as follows:

• sum:9
• id:5

In the second loop the values of variables are as follows:

• sum:45
• id:0

And Category count[1]=14

Now the first for loop ends.

Now in the second for loop snippet:

for (i = 0; i < NUM_CATEGORIES; i++)
{
if (categoryCount[i] % 2 == 0)
{
printf("Category %d has %d items\n", i, categoryCount[i]);
}
}

If the categoryCount we got in the above is even then it is printed and hence when we run the program the output it generated is :

Hope this helps!!!