Passing C++ array to function

Question

I cannot figure out how to pass the sales[] array to the BubbleSort() function. The error I'm getting is that sales was not declared in this scope, like it's an undeclared variable. That's the only issue I'm having with everything. If I don't call the function, the program works fine.

#include <iostream>
#include <fstream>
#include <string>
using namespace std;
void BubbleSort(int arr[], int n)
{
 for (int i = 0; i < n; ++i)
 for (int j = 0; j < n; ++j)
 if (arr[j] > arr[j + 1])
 {
 int temp = arr[j];
 arr[j] = arr[j + 1];
 arr[j + 1] = temp;
 }
}
int main() {
 //Variables
 //String to hold user data file
 string fileName;
 //Double to hold calculated sales average
 double averageSales;
 // Double to hold total sales
 double totalSales;
 // Int to read array size
 int arraySize;
 // Double to hold highest sales value
 double highest = 0;
 // Double to hold lowest sales value
 double lowest;
 // Char to hold rerun choice, default value is no
 char rerun = 'n';
 //Do / While loop for rerun choice
 do {
 //Get File Name from User
 cout << "Input Filename to read:" << endl;
 cin >> fileName;
 cout << "File Name: " << fileName << endl;
 // Open files stream
 ifstream file;
 file.open(fileName.c_str());
 //Check File Steam
 if (file.is_open()) {
 // Read arraySize Variable from first line of file
 file >> arraySize;
 // Create array from arraySize variable; read from file
 double sales[arraySize];
 // Read data into array
 for (int i = 0; i<arraySize; i++) {
 file >> sales[i];
 }
 // Find Total Sales & Average
 for (int i = 0; i<arraySize; i++) {
 totalSales += sales[i];
 }
 averageSales = totalSales / arraySize;
 //Find largest Sales
 for (int i = 0; i<arraySize; i++) {
 if (sales[i] > highest) {
 highest = sales[i];
 }
 }
 //Find lowest Sales - set default lowest value to the highest value
 lowest = highest;
 for (int i = 0; i<arraySize; i++) {
 if (sales[i] < lowest) {
 lowest = sales[i];
 }
 }
 //Close File stream
 file.close();
 }
 else {
 cout << "Error Opening File" << endl;
 }
 //Sort Array
 BubbleSort(sales, arraySize);
 //Output Sales data
 cout << "Total Sales: " << totalSales << endl;
 cout << "Average Sales: " << averageSales << endl;
 cout << "Highest Sales amount: " << highest << endl;
 cout << "Lowest Sales Amount: " << lowest << endl;
 //Choice to rerun
 cout << endl << "Would you like to run again? Y/N " << endl;
 cin >> rerun;
 } while (rerun == 'y' || rerun == 'Y');
}

• victor: Shouldnt this: BubbleArray(sales, arraySize); be this BubbleSort(sales, arraySize); ?
• François Andrieux: double sales[arraySize]; is not portable c++. The size of an array must be a compile time constant. Some compilers allow it through extensions but it is not standard. Consider std::vector<double> sales(arraySize); instead.
• aschepler: sales is declared inside your if (file.is_open()) block and is only valid inside it. Also, double sales[arraySize]; is not valid C++ when arraySize is not a constant expression, although some compilers accept it as an extension. Use std::vector instead of an array.
• 463035818_is_not_an_ai: you need to read about scope. The array is indeed not declared in the scope you are trying to use it.
• Lefsler: @JasonBrown, just as a tip, if you are using C++ study the STL. check std::vector it will help you A LOT

Answer 1

First, you declare variable sales inside an if-block, whereas you call BubbleSort outside of this if-block. Hence, the variable is out of scope and cannot be used for the call.

Further, note that void BubbleSort(int arr[], int n) expects an integer array, while sales is an array of doubles, i.e. double sales[arraySize].

Calling BubbleSort(sales, arraySize) should yield a compiler error once you have corrected the scope issue.

Answer 2

You have declared your array inside 'if' block. It exists only there. Moreover, 'sales' is array of doubles, but your function expects an array of integers.