help with arrays

**sal817** · 09-17-2004

hey guys,
i'm a newbie and need some assistance to begin my assignment.
Well i need to prompt the user with a category(i.e. cd's) and ask
three questions "What is the amount in stock, the average price, and how sell percentage". Basically i need to do this 10 times for ten different categories,ask the same three question, and output all info,but must be store in 3 arrays. Any suggestions?

thanks,
sal

**bithub** · 09-17-2004

I dont see where 3 arrays is necessary. Create a structure which holds all the info that you need. Then create an array of 10 of those structures, then fill the array.

Here is what the stucture could look like:

Code:

struct Information
{
    char szCategory[64];
    int nStock;
    float fPrice;
    float fSellPercentage;
};

**sand_man** · 09-17-2004

if he is learning how to use arrays, then i don't think he would have learnt to use structs yet.
sal817: don't you have some kind of program development procedure to follow? what you are asking help for is quite simple. Try to write a solution and show us what you some up with first

**dayknight** · 09-17-2004

basically u need to make 3 arrays

like

Code:

int myArray[10];

for (int x=0; x<10;x++)
  myArray[x] = 99;

this is going to fill the array with number 99
so basically

myArray[0]=99
myArray[1]=99
myArray[2]=99
myArray[3]=99
...
myArray[9]=99

**sal817** · 09-17-2004

Thanks sand_man,
I'll try to come up with code and repost. One more question, how do i prompt the user to select a categorey of 10 and then go to the array to store info and after info is store return to menu and select a different category and do the same process again.

**dayknight** · 09-17-2004

you could use "cases" or simply use a do while loop.
example:

do {

...some code

}while (until this happens);

Ask the user for the input then create an array. ex:

Code:

cout << "Enter array size: ";
cin >> arraySize;
int myArray[arraySize];

do {

... some code

}while();

**itsme86** · 09-17-2004

Originally Posted by dayknight

Code:

cout << "Enter array size: ";
cin >> arraySize;
int myArray[arraySize];

do {

... some code

}while();

Please no...couple of things wrong with that:

1) Variable definitions should come before any code.
2) That's C++ code, not C.

**Hunter2** · 09-17-2004

>>how do i prompt the user to select a categorey of 10
Use scanf and printf

>>then go to the array to store info
Store info in array[category_index]

>>return to menu and select a different category
As has been mentioned, stick the menu->store code in a loop.

Code:

while(!done)
{
   //Display menu and get input
   //Do your storing stuff
}

And to get it to break out of the loop properly, you'll have to juggle it around into some arrangement that quits the loop when the input says 'quit' or something.

**sand_man** · 09-17-2004

Code:

#include <stdio.h>

int main(void)
{
    int amount_in_stock[10];
    int avg_price[10];
    int sell_percentage[10];
    int i;
    
    
    for(i=0;i<10;i++)
    {
        scanf("%d",&amount_in_stock[i]);
        scanf("%d",&avg_price[i]);
        scanf("%d",&sell_percentage[i]);       
    }    
    return 0;
}

**Prelude** · 09-17-2004

Originally Posted by sand_man

Code:

#include <stdio.h>

int main(void)
{
    int amount_in_stock[10];
    int avg_price[10];
    int sell_percentage[10];
    int i;
    
    
    for(i=0;i<10;i++)
    {
        scanf("%d",&amount_in_stock[i]);
        scanf("%d",&avg_price[i]);
        scanf("%d",&sell_percentage[i]);       
    }    
    return 0;
}

Code:

#include <stdio.h>

int main ( void )
{
  int stock[10];
  int avg_price[10];
  int percent_sold[10];
  int i;

  for ( i = 0; i < 10; i++ ) {
    if ( scanf ( "%d%d%d", &stock[i], &avg_price[i], &percent_sold[i] ) != 3 ) {
      /* Handle an input error */
    }
  }

  return 0;
}

Always check the return value from input functions. And in this case there's no good reason to split up the calls to scanf. By splitting the calls you can better diagnose errors, but at this level of programming it's better to just print an error message and bail than to make any real attempt at recovery.

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