ofstreamエラー

Question

これは私が尋ねた別の質問を参考にしていますが、それは完全に独自の質問です。

私は2つのエラーを取得コンパイルします。>

1を\ asst4.cpp（73）：エラーC2065： 'OUTFILE'：宣言されていない識別子

1> \ asst4.cpp（73）。 ：エラーC2228： '.close'の左側にクラス/構造体/共用体が必要です

私はここで間違って行ったことについて少し混乱していますか？お礼やアイデアはありますか？ （実際のOUTFILEは、コードの先頭付近にあるここ

完全なコードです：。

#include<iostream> 
#include<fstream> //used for reading/writing to files. 
#include<string> //needed for the filename. 
#include<stdio.h> //for goto statement 

using namespace std; 

int main() 
{ 
    string start; 
    char choice; 
    char letter; 
    int x; 
    int y; 
    int z; 
    string filename; 
    int garbage = rand()%('!' - '~' + 1); 
    cout << "Would you like to encrypt or decrypt a file? Please type enc, dec, or stop (case sensitive): " ; 
    cin >> start; 
    while(start == "enc") 
    { 
     x = 1; 
     y = 1; 
     cout << "How many garbage characters would you like between each correct character?: " ; 
     cin >> z; 
     cout << endl << "Please insert the name of the document you wish to encrypt, make sure you enter the name, and the file type (ie: filename.txt): " ; 
     cin >> filename; 
     ifstream infile(filename.c_str()); 
     while(!infile.eof()) 
     { 
      ofstream outfile("encrypted.txt", ios::out); 
      infile.get(letter); 
      if (x == y)   
       { 
       outfile << garbage; 
       x++;    
      } 
      else 
      { 
       if((x - y) == z)    
       { 
        outfile << letter;   
        y = x;     
       } 
       else       
       {       
        outfile << garbage; 
        x++; 
       } 
      } 
     } 
     cout << endl << "Encryption complete...please return to directory of program, a new file named encrypted.txt will be there." << endl; 
     infile.close(); 
     outfile.close(); 
     cout << "Do you wish to try again? Please press y then enter if yes (case sensitive)."; 
     cin >> choice; 
     if(choice == 'y') 
     { 
      start = "enc"; 
     } 
     else 
     { 
      cout << endl << "Do you wish to decrypt a file? Please press y then enter if yes (case sensitive)."; 
      if(choice = 'y') 
      { 
       start == "dec"; 
      } 
      else 
      { 
       start == "no"; 
      } 
     } 
    } 
    while(start == "dec") 
    { 

     //lets user choose whether to do another document or not. 
     //used to track each character in the document. 
     x = 1; //first counter for tracking correct letter. 
     y = 1; //second counter (1 is used instead of 0 for ease of reading, 1 being the "first character"). 
       //third counter (used as a check to see if the first two counters are equal). 
     //allows for user to input the filename they wish to use. 
     cout << "Please make sure the document is in the same file as the program, thank you!" << endl << "Please input document name: " ; 
     cin >> filename; //getline(cin, filename); 
     cout << endl; 
     cout << "'Every nth character is good', what number is n?: "; 
     cin >> z; //user inputs the number at which the character is good. IE: every 5th character is good, they would input 5. 
     cout << endl; 
     z = z - 1; //by subtracting 1, you now have the number of characters you will be skipping, the one after those is the letter you want. 
     ifstream infile(filename.c_str()); //gets the filename provided, see below for incorrect input. 
     if(infile.is_open()) //checks to see if the file is opened. 
     { 
      while(!infile.eof()) //continues looping until the end of the file. 
      { 
        infile.get(letter); //gets the letters in the order that that they are in the file. 
        if (x == y)   //checks to see if the counters match... 
        { 
         x++;    //...if they do, adds 1 to the x counter. 
        } 
        else 
        { 
         if((x - y) == z)   //for every nth character that is good, x - y = nth - 1. 
         { 
          cout << letter;   //...if they don't, that means that character is one you want, so it prints that character. 
          y = x;     //sets both counters equal to restart the process of counting. 
         } 
         else      //only used when more than every other letter is garbage, continues adding 1 to the first 
         {       //counter until the first and second counters are equal. 
          x++; 
         } 
        } 
      } 
      cout << endl << "Decryption complete...please return to directory of program, a new file named encrypted.txt will be there." << endl; 
      infile.close(); 
      cout << "Do you wish to try again? Please press y then enter if yes (case sensitive)."; 
      cin >> choice; 
      if(choice == 'y') 
      { 
       start == "dec"; 
      } 
      else 
       { 
       cout << endl << "Do you wish to encrypt a file? Please press y then enter if yes (case sensitive)."; 
       if(choice == 'y') 
       { 
        start == "enc"; 
       } 
       else 
       { 
        start == "no"; 
       } 
      } 
     } 
     else //this prints out and program is skipped in case an incorrect file name is used. 
     { 
      cout << "Unable to open file, please make sure the filename is correct and that you typed in the extension" << endl; 
      cout << "IE:" << "  filename.txt" << endl; 
      cout << "You input: " << filename << endl; 
      cout << "Do you wish to try again? Please press y then enter if yes (case senstive)." ; 
      cin >> choice; 
      if(choice == 'y') 
      { 
       start == "dec"; 
      } 
      else 
      { 
       start == "no"; 
      } 
     } 
     getchar(); //because I use visual C++ express. 
    } 
} 

おかげで事前に ジェフ

Answer 1

スコープの問題は、あなたがあなたの中の中outfileを宣言しています！。ループ、まだそれにアクセスしようとしている外の言っwhileループ。

あなたwhile(!infile.eof())の前にある行に移動ofstream outfile("encrypted.txt", ios::out);右あなたのifstream infile(filename.c_str());後。

Answer 2

あなたはoutfile.close（）の呼び出しがoutfileの宣言と同じスコープ内に存在しないため、outfile.close（）の呼び出しがコンパイルされない理由がX-istenceに言及しています。

）（それはINFILEと同じスコープ規則に従うようにするには、whileループの外ライン

ofstream outfile("encrypted.txt", ios::out); 

を移動できるのいずれか、またはあなたがoutfile.closeためにあなたの呼び出しを移動することができます。 whileループの内部では、outfileが存在する現在のスコープに移動します。

私の好みは、ファイルを開くことは非常に高価な操作であり、あなたが本当にinfileから読んだすべての文字に対してこれをしたくないので、whileループの外側でoutfileの宣言を動かすことでしょう。一度それを開いて、一度閉じると、この場合に行く方法です。