Question

C program help:

Write a C program that uses three functions to perform the following tasks: – The first function should read the price of an item sold at a grocery store together with the quantity from the user and return all the values to main().

example:

#include

void getInput(int *pNum1, int *pNum2); // note: *pNum1 & *pNum2 are pointers to ints

int main ()
{

   int numDucks,numCats;

   getInput(&numDucks, &numCats); // passing addresses of num1 & num2 to getInput()

   printf("\nYou have %d ducks and %d cats\n\n",numDucks, numCats);

   return 0;
}

// Gets 2 numbers from user via pointers
void getInput(int *pNum1, int *pNum2)
{
   printf("Enter num ducks: ");
   scanf("%d",pNum1); // note no '&' on pNum1 because pNum1 is already an address
   printf("Enter num cats: ");
   scanf("%d",pNum2); // note no '&' on pNum2 because pNum2 is already an address
}

  The second function should calculate and return the total purchase price for the item.
The last function should display the price, quantity and the total purchase price. The user should be given a choice to continue with another item. If 'n' is entered the program displays the grand total price of all the items purchased and terminates.

Question: This is my code, why is always sum the first inputs, but it should be back to intital, and then get all sum of vaule. Thanks for your patient.

#include <stdio.h>
#include <math.h>
void readprice(int*quantity, int*price){
   printf("Enter the number of the items:\n");
   scanf("%d",quantity);/*read the number of items*/
   printf("Enter the price of item:\n");
   scanf("%d",price);/*read the price of items*/
}
void Display(int quantity,int price,int value)
{
   printf("the number of items: %d \nthe price of items: %d \nthe total value of items: %d\n",quantity,price,value);/*diplay the quantity price and value*/
}
int totalPrice(int quantity,int price)
{
   return price*quantity;/*the fuction for caculate the total price*/
}
void main ()
{
char Y_N;
   while(1){
   int quantity;
   int price;
   int sum=0;
   int value=0;
   readprice(&quantity,&price);
       value=value+totalPrice(quantity,price);
       Display(quantity,price,value);
       printf("Do you want run the program agaian ?, if not please enter(n):\n");
       scanf(" %c",&Y_N);
   if (Y_N=='n'){
       sum= sum+value;/* the sum value*/
       printf("the sum of total prices:%d",sum);
       system("pause");
   }
   }
}

Answer 1

thanks for the question, your problem overall looks good, but you have made mistake in declaring the sum and and also some calculation mistakes which i have corrected. Now the program is working fine.

Here is the updated code

===================================================================================

#include <stdio.h>

// no need to include math.h library

void readprice(int*quantity, int*price)

{

    printf("Enter the number of the items: ");

    scanf("%d",quantity);/*read the number of items*/

    printf("Enter the price of item: ");

    scanf("%d",price);/*read the price of items*/

}

void Display(int quantity,int price,int value)

{

    printf("The number of items: %d \nThe price of items: $%d \nthe total value of items: $%d\n",quantity,price,value);/*display the quantity price and value*/

}

int totalPrice(int quantity,int price)

{

    return price*quantity;/*the function for calculate the total price*/

}

void main ()

{

    char Y_N;

    int sum=0; // you need to declare it outside while loop

  while(1)

    {

        int quantity;

        int price=0;

        int value=0;

        readprice(&quantity,&price);

        value=totalPrice(quantity,price);

        sum= sum+value;/* the sum value*/

        Display(quantity,price,value);

        printf("Do you want run the program again ?, if not please enter(n):\n");

        scanf(" %c",&Y_N);

        if (Y_N=='n')

        {

            printf("the sum of total prices $:%d",sum);

            break; // break out of while loop

        }

   }

}

===================================================================================