將已編輯的infile文件保存到C++的輸出文件中問題

Question

我在這裏編碼的最後一部分存在問題。 //將文件從infile複製到outfile。該程序傳輸我的infile，它只是一個8位數的編號，20392207，使用.at方法將它分成單獨的數字;並應該將該輸出保存到outfile中。我不知道如何將輸出保存到outfile。有什麼建議？

INFILE如下所示

20392207 

程序的輸出看起來像這樣

The input number :20392207 
The number 1:2 
The number 2:0 
The number 3:3 
The number 4:9 
The number 5:2 
The number 6:2 
The number 7:0 
The number 8:7 

了outfile應該看起來像節目出來放，而是看起來就像infile中的精確副本。

#include<iostream> 
#include<fstream> 
#include<cstdlib> 
#include<string> 
#include<cmath> 
using namespace std; 
int main() 
{ 
    string ifilename, ofilename, line, line2; 
    ifstream inFile, checkOutFile; 
    ofstream outFile; 
    char response; 
    int i; 


    // Input file 
    cout << "Please enter the name of the file you wish to open : "; 
    cin >> ifilename; 
    inFile.open(ifilename.c_str()); 
    if (inFile.fail()) 
    { 
     cout << "The file " << ifilename << " was not successfully opened." << endl; 
     cout << "Please check the path and name of the file. " << endl; 
     exit(1); 
    } 
    else 
    { 
     cout << "The file is successfully opened." << endl; 
    } 


    // Output file 
    cout << "Please enter the name of the file you wish to write : "; 
    cin >> ofilename; 
    checkOutFile.open(ofilename.c_str()); 
    if (!checkOutFile.fail()) 
    { 
     cout << "A file " << ofilename << " exists.\nDo you want to continue and overwrite it? (y/n) : "; 
     cin >> response; 
     if (tolower(response) == 'n') 
     { 
      cout << "The existing file will not be overwritten. " << endl; 
      exit(1); 
     } 
    } 
    outFile.open(ofilename.c_str()); 
    if (outFile.fail()) 
    { 
     cout << "The file " << ofilename << " was not successfully opened." << endl; 
     cout << "Please check the path and name of the file. " << endl; 
     exit(1); 
    } 
    else 
    { 
     cout << "The file is successfully opened." << endl; 
    } 



    // Copy file contents from inFile to outFile 
    while (getline(inFile, line)) 
    { 
    cout << "The input number :" << line << endl; 
     for (i = 0; i < 8; i++) 
     { 
      cout << "The number " << i + 1 << ":"; 
      cout << line.at(i); 
      cout << endl; 
     } 

    outFile << line << endl;  
    } 



    // Close files 
    inFile.close(); 
    outFile.close(); 
} // main 

Answer 1

您需要在while(getline(inFile, line))循環內寫入outFile。

[編輯]參見user4581301的回答，以獲得更徹底的治療。

Answer 2

在這裏我們可以看到，outFile只寫到while循環之外：

while (getline(inFile, line)) 
{ 
    cout << "The input number :" << line << endl; 
    for (i = 0; i < 8; i++) 
    { 
     cout << "The number " << i + 1 << ":"; 
     cout << line.at(i); 
     cout << endl; 
    } 
} 
outFile << line << endl; 

它沒有包含相同的輸出控制檯

解決方案的機會：寫循環內的

while (getline(inFile, line)) 
{ 
    cout << "The input number :" << line << endl; 
    outFile << "The input number :" << line << endl; 
    blah blah blah 
} 

但是，這看起來像廢話和功能通過消除重複使得像一個更好的解決方案和：這是寫入到控制檯同樣的東西提高可重用性。

void output(std::ostream & out, 
      const std::string & line) 
{ 
    out << "The input number :" << line << endl; 
    for (int i = 0; i < 8; i++) 
    { 
     out << "The number " << i + 1 << ":"; 
     out << line.at(i); 
     out << endl; 
    } 
} 

，並呼籲：

while (getline(inFile, line)) 
{ 
    output(cout, line); 
    output(outFile, line); 
}