如何調用函數，將寫入文件，並在該函數內調用其他函數

Question

您好im學習c + +和我想知道如何我可以調用將寫入文件的函數。在該功能中，它將調用其他功能並打印輸出。我會怎麼做？

#include <iostream> 
#include <fstream> 
#include <string> 
using namespace std; 

void buildArray(float arrayScores[], int numOfScores); 
void printOutArray(float arrayScores[], int numOfScores); 
void writeToFile(float arrayScores[], int numOfScores); 

int main(){ 

    int numOfScores; 
    cout << "Enter the number of scores: " 
    cin >> numOfScores; 

    float *arrayScores = nullptr; 
    arrayScores = new float [numOfScores]; 
    writeToFile(arrayScores, numOfScores); 
    delete [] arrayScores; 
} 

void buildArray(float arrayScores[], int numOfScores){ 
    float score = 0; 
    for (int i=0; i<numOfScores; i++){ 
    cout << "Enter the score: "; 
    cin >> score; 
    arrayScores[i] = score; 
} 

void printOutArray(float arrayScores[], int numOfScores){ 
    int Items = numOfScores; 
    for (int i = 0; i<numOfScores; i++){ 
     float grade = arrayScores[i]; 
     cout << "Score number " << i+1 << ": " << arrayScores[i] << endl; 
    } 

} 

void writeToFile(arrayScores[], int numOfScores){ 
    ofstream outfile; 
    outfile.open("Scores.txt"); 
    outfile << buildArray(arrayScores,numOfScores); 
    outfile << printOutArray(arrayScores,numOfScores); 
    outfile.close(); 
} 

Answer 1

outfile << buildArray(arrayScore, numOfScores); 

嘗試發送由buildArray返回outfile的值。但是你已經聲明buildArray不會返回任何東西！您已通過在其聲明（和定義）中的名稱前寫入void來完成此操作。

你有兩個選擇

1. 回報什麼，那就是你要打印，爲buildArray結果。
2. 代替發送結果的buildArray到outfile的，通outfile作爲參數傳遞給buildArray和發送日期outfile的buildArray體內。

下面是一些代碼，讓你用第二個想法去。

#include <ostream> 

void buildArray(std::ostream& outfile, float arrayScores[], int numOfScores){ 
    float score = 0; 
    for (int i=0; i<numOfScores; i++){ 
    cout << "Enter the score: "; 
    cin >> score; 
    arrayScores[i] = score; 
    outfile << /* whatever you want to write goes here */ 
} 

注意要點：

1. 包含了ostream頭。
2. 爲函數添加一個參數，用於要使用的文件流。
3. 使用函數內部的流，顯示在主體的最後一行。