Question

C programming course. Cannot use global variables.

This is the assignment:

In this project you will calculate the maximum profit you could have made by trading a single stock over a period of one month. You will assume that you bought rounded stock units (usually in hundreds, or tens) worth between $3000 and $5000 at the best possible“closing” price during the period and sold it at the best possible “closing” price. You will assume that you are permitted to buy your units just once during this period and then sell it just once. You have to buy them before you can sell them (long trading only, no shorts).

I need help coding these two functions:

double getMinPrice(double* pPrices, int size);

scans the array for the lowest value and returns the the minimum price as a double.

double getMaxPrice(double* pPrices, int size);

Scans the array for the highest value and returns the maximum price as a double.

I have created a .txt in my project folder containing these values: (closing price of the stock CRON)

7.7

7.7

7.42

7.05

6.8

7.78

8.11

7.63

8.34

8.52

9.71

10.72

10.65

11.52

11.74

9.86

9.05

9.6

9.34

9.7

9.77

10.22

10.69

10.72

11.32

This is my code so far. Please show me how to creat those two functions. the max and min. they have to be verbaitum.

#define _CRT_SECURE_NO_WARNINGS

#define _NUMB_OF_STOCKS 30

#include <stdio.h>

#include <string.h>

void banner();

void readPrices();// char* fileName, int pricesCapacity, double* pPrices, int* pricesSize);

/*double getMinPrice(double* pPrices, int size);

double getMaxPrice(double* pPrices, int size);

void profitableTrades(double* pPrices, int pricesSize, double* pProfits, int* pProfitsSize);

void save(char* filename, double* pProfits, int profitsSize);

void print(double* pProfits, int profitsSize);*/

void banner() {

   printf("Welcome to Stock Trading \n");

   printf("xxxxxxxxxxxxxxxxxxxxxxxx\n\n");

}

void readPrices() {

   char prices[_NUMB_OF_STOCKS];

   char* stockPrices = "prices.txt";

   long charsRead = 0;

   FILE* pFile = 0;

   pFile = fopen(stockPrices, "r");

   if (pFile) {

      while (fgets(prices, _NUMB_OF_STOCKS, pFile) != NULL) {

          charsRead = strlen(prices);

          printf("Closing price: %s\n", prices);

        }

   }else {

      printf("Error opening %s file for read\n", stockPrices);

   }

if(pFile) fclose(pFile);

}

double getMinPrice(double* pPrices, int size) {

}

void test() {

  

   banner();

   readPrices();

   // getMinPrice();

   // getMaxPrice();

   // profitableTrades();

   // save();

   // print();

}

int main() {

   test();

   return 0;

}

Answer 1

#define _CRT_SECURE_NO_WARNINGS
#define _NUMB_OF_STOCKS 30
#include <stdio.h>
#include <string.h>

void banner();
void readPrices();

double getMinPrice(double* pPrices, int size);
double getMaxPrice(double* pPrices, int size);
/*
void profitableTrades(double* pPrices, int pricesSize, double* pProfits, int* pProfitsSize);
void save(char* filename, double* pProfits, int profitsSize);
void print(double* pProfits, int profitsSize);
*/
void banner()
{
   printf("Welcome to Stock Trading \n");
   printf("xxxxxxxxxxxxxxxxxxxxxxxx\n\n");

}

void readPrices()
{

   char prices[_NUMB_OF_STOCKS];
   char* stockPrices = "data.txt";
   long charsRead = 0;
   
   FILE* pFile = 0;
   
   pFile = fopen(stockPrices, "r");
   
   if (pFile)
   {
      while (fgets(prices, _NUMB_OF_STOCKS, pFile) != NULL) 
      {
         charsRead = strlen(prices);    
         printf("Closing price: %s\n", prices);
      }
   
   }
   else
   {
      printf("Error opening %s file for read\n", stockPrices);
   }

   if(pFile)
      fclose(pFile);

}

double getMinPrice(double* pPrices, int size) {
   
   int i, min = pPrices[0];

   for(i = 1; i < size; i++)
   {
      if(min > pPrices[i])
         min = pPrices[i];
   }

   return min;
}

double getMaxPrice(double* pPrices, int size) {
   
   int i, max = pPrices[0];

   for(i = 1; i < size; i++)
   {
      if(max < pPrices[i])
         max = pPrices[i];
   }

   return max;
}


void test() {

   banner();

   readPrices();

   //test double array for testing getMInPrice and getMaxPrice function

   double price[] = { 34.56, 56.34, 12.34, 89.43, 67.234, 343.3, 535.5 };

   printf("\nMin : %lf", getMinPrice(price, 7));
   
   printf("\nMax : %lf", getMaxPrice(price, 7));
   
   //     profitableTrades();
   
   //     save();
   
   //     print();

}

int main() {

   test();

   return 0;

}

$Select C:\Users\TusharDesktopne.profit.ee Closing price: 7.63 Closing price: 8.34 Closing price: 8.52 Closing price: 9.71 Closing price: 10.72 Closing price: 10.65 Closing price: 11.52 Closing price: 11.74 Closing price: 9.86 Closing price: 9.05 Closing price: 9.6 Closing price: 9.34 Closing price: 9.7 Closing price: 9.77 Closing price: 10.22 Closing price: 10.69 Closing price: 10.72 Closing price: 11.32 Min 12.88888e Max 535.888ee Process exited after 0.1257 seconds with return value 0 Press any key to continue . . .$

Note: The required functions are implemented and tested with the test array. For any query or optimization drop a comment.