Filling an array with random numbers

Do you mean to have a prototype that doesn't match the actual call, that again doesn't match the function itself?

Todd

Quote:

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Originally Posted by Todd Burch

Do you mean to have a prototype that doesn't match the actual call, that again doesn't match the function itself?

Todd

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....hmmm, that may well be the problem... thanks :s

i think ive sorted that out... now on to the next one :rolleyes:

i now get told that 'called object is not a function' for the following line from main

Code:

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    else{
            generatePrices( firstEntry);
             averagePrice( startDay, endDay );
            }
    return 0;

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This baffles me...

(genuinely sorry for all the noob questions, i know how irritating it is..)

Similar to before, your function call does not match the function prototype or the function definition itself.

Todd

I cant see what else i can do to them, arrrg i think ill just give it in as it is, at least i gave it a go. Thanks to all who replied

Code:

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#include <stdio.h>

void generatePrices(float *firstEntry);
float averagePrice(int *startDay, int *endDay);
const int NUMDAYS = 14;  //constant used as size of the array


int main()
{
    int firstDay, lastDay;
    int *startDay = &firstDay;  //creates a pointer to firstDay
    int *endDay = &lastDay;    //creates a pointer to lastDay
    float beginPrice, averagePrice;
    float *startPrice = &beginPrice;
    float prices[NUMDAYS]; //declares array 'prices' of size NUMDAYS
   
    printf ("Welcome to stock tracker\n");
    printf ("To begin, please enter the starting price of the share you wish to track: ");
    scanf ("%f", &beginPrice);  //sarting price entered by user and stored as firstEntry
    prices[0] = beginPrice;
   
    float *firstEntry = &prices[0];
   
    printf ("\nPlease enter the day you wish to track from (1 - 14): ");
    scanf ("%d", &firstDay);
    startDay -= 1;
    printf ("\nPlease enter the day you wish to track to (1 - 14): ");
    endDay -= 1;
    scanf ("%d", &lastDay);  //startDay and endDay entered by user and sent to variables
   
    if ( firstDay < 0 || firstDay > NUMDAYS || lastDay < 0 || lastDay > NUMDAYS || lastDay < firstDay || firstDay == lastDay)
    {
        printf ("\nError: please check that days are within range 1 - 14 and startDay is lower than EndDay");
    } //inputs checked for errors
    else{
            generatePrices( firstEntry);
            averagePrice( startDay, endDay);
            }
    return 0;
}  //end of main function

/* *************************************************************************************************** */

void generatePrices(float *firstEntry)
{
    int i, j;

    j = (int) *firstEntry; //cast firstEntry as an int

    for (i=1; i < (NUMDAYS - 1); i++)
    {
        prices[i] = j - 0.5 + rand() % j + 1.5;  //generates prices for share
        }
}

/* ***************************************************************************************************** */

float averagePrice(int *startDay, int *endDay)
{
      float sum = 0.0, average;
      int k;
     
      for (k = startDay; k < endDay; k++ ) {
            sum += prices[k];
            }
        average = (sum / NUMDAYS);        //calculate average price
        return (average);                  //return averahe to main
}

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This might help you get better fluctations. It's just a simple linear interpolation that chooses a random coefficient.

Code:

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float GetRandomFloatRange(float min,float max)
{
  float coef = ((float)(rand () % 10000))/10000.0f;

  return min + coef *(max-min);
}

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Keep in mind rand() is a very crappy pseudo random number generator.

See here:

Code:

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#include <stdio.h>

void generatePrices(float *firstEntry);
float averagePrice(int *startDay, int *endDay);
const int NUMDAYS = 14;  //constant used as size of the array


int main()
{
    int firstDay, lastDay;
    int *startDay = &firstDay;  //creates a pointer to firstDay
    int *endDay = &lastDay;    //creates a pointer to lastDay
    float beginPrice, averagePrice; // Is this a variable or a function name?  It's BOTH!!
    float *startPrice = &beginPrice;
    float prices[NUMDAYS]; //declares array 'prices' of size NUMDAYS
   
    printf ("Welcome to stock tracker\n");
    printf ("To begin, please enter the starting price of the share you wish to track: ");
    scanf ("%f", &beginPrice);  //sarting price entered by user and stored as firstEntry
    prices[0] = beginPrice;  // local to main!!
   
    float *firstEntry = &prices[0];
   
    printf ("\nPlease enter the day you wish to track from (1 - 14): ");
    scanf ("%d", &firstDay);
    startDay -= 1;
    printf ("\nPlease enter the day you wish to track to (1 - 14): ");
    endDay -= 1;
    scanf ("%d", &lastDay);  //startDay and endDay entered by user and sent to variables
   
    if ( firstDay < 0 || firstDay > NUMDAYS || lastDay < 0 || lastDay > NUMDAYS || lastDay < firstDay || firstDay == lastDay)
    {
        printf ("\nError: please check that days are within range 1 - 14 and startDay is lower than EndDay");
    } //inputs checked for errors
    else{
            generatePrices( firstEntry);
            averagePrice( startDay, endDay); // Where is the returned value assigned???
            }
    return 0;
}  //end of main function

/* *************************************************************************************************** */

void generatePrices(float *firstEntry)
{
    int i, j;

    j = (int) *firstEntry; //cast firstEntry as an int

    for (i=1; i < (NUMDAYS - 1); i++)
    {
        prices[i] = j - 0.5 + rand() % j + 1.5;  //generates prices for share
        }
}

/* ***************************************************************************************************** */

float averagePrice(int *startDay, int *endDay)
{
      float sum = 0.0, average;
      int k;
     
      for (k = startDay; k < endDay; k++ ) {
            sum += prices[k];
            }
        average = (sum / NUMDAYS);        //calculate average price
        return (average);                  //return averahe to main
}

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Todd