Question

我无法弄清楚如何将sales[]数组传递给BubbleSort()函数。我得到的错误是销售未在此范围内声明，就像它是一个未声明的变量。这是我遇到的唯一问题。如果我不调用该函数，程序运行正常。

#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');
}

Answer 1

首先，在sales - 块中声明变量if，而在此BubbleSort - 块之外调用if。因此，变量超出范围，不能用于调用。

此外，请注意void BubbleSort(int arr[], int n)需要一个整数数组，而sales是一个双精度数组，即double sales[arraySize]。

一旦纠正了范围问题，调用BubbleSort(sales, arraySize)就会产生编译错误。

Answer 2

你已经在里面宣布你的阵列＆＃39;如果＆＃39;块。它只存在于那里。此外，＆＃39;销售＆＃39;是双精度数组，但是你的函数需要一个整数数组。

将C ++数组传递给函数

2 个答案: