如何糾正運行時錯誤堆棧周圍的變量是否損壞？

Question

我正在使用指針的madlibs程序。當我嘗試構建它時，它的確如此正確，但我認爲它們在動態分配數組時遇到了一些問題，這些數組用於存儲讀取的文本文件中的行。陣列中的數字是文件中的標記值。我還在cout語句中顯示它在錯誤發生前存儲信息。可以幫助嗎？錯誤是圍繞「條目」的堆棧。

//這裏是我到目前爲止的代碼

#include <iostream>  
#include <string>   
#include <fstream> 
#include <sstream> 




using namespace std; 

void header(); 
//string play_again(); 
void read_game_file(string **entries, int *num_entries, string **story, int *num_lines); 
//string get_user_input(string* entries, int * num_entries); 

int main() 
{ 

    header(); 
    cout<<endl<<endl; 

    int num_entries=(NULL); 
    int *num_lines=(NULL); 
    string *entries (NULL); 
    string *story (NULL); 

    read_game_file(&entries, &num_entries, &story, &*num_lines); 
    cout<<"doneszo"<<endl; 
    string get_user_input(string*entries, int * num_entries); 


} 

void header() 
{ 
    cout<<"Hello! Welcome to the game Madlibs."<<endl; 
    cout<<"The object of the game is to produce something that sounds totally ridiculous."<<endl; 
    cout<<"So don't think to hard about your answers."<<endl; 
    cout<<"At the top, you will see a bunch of word descriptions followed by blank spaces."<<endl; 
    cout<<"Type your word in the blanks. The words should match the descriptions on the left."<<endl; 
    cout<<"Enter no when you no longer wish to play. Enter yes to continue. Have a great laugh!"<<endl; 
} 

void read_game_file(string **entries, int *num_entries, string **story, int *num_lines) 
{ 
    //Ask user to input file name and opens file 
    ifstream mad_lib; 
    string file_name; 

    cout<<"Please enter the file name with extension: "; 
    cin>>file_name; 
    mad_lib.open(file_name); 

    //Checks to see that file name is valid if not ask for input again 
    if (!mad_lib) 
    { 
     cout<<"File could not be opened. Please try again"<<endl; 
     cout<<"Please enter the file name with extension: "; 
     cin>>file_name; 
     mad_lib.open(file_name); 
     } 

    int work; 
    string line; 
    mad_lib>>work; 
    num_entries=&work; 
    getline(mad_lib,line); 

    *entries=new string[*num_entries]; 
    cout<<*num_entries<<endl; 
    string * entry; 
    for(int i=0; i<*num_entries; i++) 
    { 
     entry = new string; 
     getline(mad_lib,*entry); 
     entries[i]= entry; 
     cout<<*(entries[i])<<endl; 
    } 


    string work_2; 
    int work_3; 
    stringstream ss; 
    getline(mad_lib,work_2); 
    ss<<work_2; 
    ss>>work_3; 
    cout<<work_2<<endl; 
    num_lines=&work_3; 
    *story=new string[*num_lines]; 
    string *entry_2; 

    for(int j=0; j<=*num_lines; j++) 
    { 
     entry_2=new string; 
     getline(mad_lib,*entry_2); 
     story[j]= entry_2; 
     cout<<*(story[j])<<endl; 
    } 

} 

Answer 1

不要使用函數參數指針直到必要的。

使用傳遞引用和常量來代替。

另一個問題要問自己 - 你真的想read_game_file「填充」其參數中的一些數據嗎？你能更好地設計它嗎？在這裏，你有一些在main中定義的變量，並且你期望read_game_file爲你「填充」它們。

您應該將此功能封裝在類中。將文件名作爲參數傳遞給類的方法ReadFile(const string& filename)。所有這些數據都應該在課堂上。

爲了解決立即解決問題（在不潔淨的方式）：

void read_game_file(string **entries, int *num_entries, string **story, int *num_lines); 

應該

void read_game_file(vector<string>& entries, int& num_entries, vector<string>& story, int& num_lines); 


int main() 
{ 

    header(); 
    cout << endl << endl; // spaces help readability! 

    int num_entries = 0; 
    int num_lines = 0; 
    vector<string> entries; 
    vector<string> story; 

    read_game_file(&entries, &num_entries, &story, &*num_lines); 
    cout << "doneszo"<< endl; 
    string get_user_input(vector<string>& entries, int& num_entries); 
} 

使用的載體，而不是陣列。它們優雅而乾淨。 我將離開該功能爲您完成。