C++ ifstream類型錯誤

Question

我想用C++讀取文件的內容。即時通訊使用ifstream的，但這裏有一個錯誤在編譯：

代碼：

#include <Python.h> 
#include <iostream> 
#include <fstream> 

using namespace std; 

ifstream script; 
script.open("main.py"); 
const char *programm; 
if (script.is_open()) { 
    while (!script.eof()) { 
     script >> programm; 
    } 
} 
script.close(); 

和錯誤：

main.cpp:8:1: error: 'script' does not name a type 
script.open("main.py"); 
^ 
main.cpp:10:1: error: expected unqualified-id before 'if' 
if (script.is_open()) { 
^ 

我希望你能幫助我，謝謝！

Answer 1

#include <Python.h> 
#include <iostream> 
#include <fstream> 
#include <string> 

using namespace std; 


int main(){ 

    ifstream script; 
    script.open("main.py"); 
    // const char *programm; // You don't need a C string unless you have a reason. 
    string programm; 
    if (script.is_open()) { 
     while (!script.eof()) { 
      string line; 
      script >> line; 
      line += '\n'; 
      programm += line; 
     } 
    } 
    script.close(); 
    // Now do your task with programm; 
return 0; 
} 

Answer 2

有幾個問題。主要的（導致錯誤）是在C++中，你不能只讓代碼自己生存。這一切都進入功能。特別是，您必須具有main函數。

此外，您的閱讀循環不會正常工作。您應該閱讀std::string，這將記錄您的記憶，以及您將錯過最後一個字符串的當前方式。我建議一次讀一行。就像這樣：

#include <Python.h> 
#include <iostream> 
#include <fstream> 
#include <string> 

int main() 
{ 
    std::ifstream script ("main.py"); 
    std::string line; 
    if (!script) // Check the state of the file 
    { 
     std::cerr << "Couldn't open file\n"; 
     return 1; 
    } 
    while (std::getline(script, line)) // Read a line at a time. 
     // This also checks the state of script after the read. 
    { 
     // Do something with line 
    } 
    return 0; // File gets closed automatically at the end 
}