如何取消分配數組內存？

Question

由於此輸出，我的程序停止工作。我怎樣才能釋放它？ 我試過我在我的代碼中，但沒有幫助。 完整的代碼可以在這裏找到：full code

for (i = 0 ; i < n ; i++) { 
    if (
     !((x[i] >= 0) && (x[i] <= a) & 
      (y[i] >= 0) && (y[i] <= b) 
     ) 
    ) { 
     cout << x[i] << ' ' << y[i] << ' ' << s[i] << ' ' << "SPADOL" << endl; 
    } else { 
     cout << x[i] << ' ' << y[i] << ' ' << s[i] << endl; 
    } // ALLOCATION IS DONE AT THIS POINT 

    delete [] x; 
    delete [] y; 
    delete [] s; 
} 

當我運行這段代碼，我開始輸入x和y，並在之後我鍵入y值，程序停止工作。當我只輸入一行時，程序執行完美，但是當我想要輸入多行時出現問題，..在第一個輸出打印出來後，程序崩潰。 我的全代碼載體：

#include <iostream> 
#include <string> 
#include <vector> 
#include <stdlib.h> 
#include <string> 

using namespace std; 
// vector<string> inputs; 
int n; // pocet uloh 
int a; // rozmer obdlznika a 
int b; // rozmer obdlznika b 
vector<int> x; 
vector<int> y; 
vector<string> s; 
int i; 
int d; 

static const char alpha[] = {'D', 'L', 'P'}; 
char genRandom() 
{ 
    return alpha[rand() % strlen(alpha)]; 
} 
// end of generator 


int main() { 

    cin >> n; 

    while(!((n >= 1)&&(n <=15000))) 
    { 
      cout << "max 15000" << flush; 
      cin >> n; 
      } 


    cin >> a >> b; 

    while(!((a >= 1)&&(a <=100) & (b >= 1)&&(b <= 100)&&(a!=b))) 
    { 
      cout << "chyba max 100 alebo a!=b" << endl; 
      cin >> a >> b; 
      } 


     for (i = 0; i < n; i++) 
       {  
        cout << "Uloha " << i+1 << ":" << endl; 

        cin >> x[i]; 
        cin >> y[i]; 
        cin >> s[i]; 

        while(!((x[i]>=0)&&(x[i]<=a))) { 
        cout << "Try Again x: " << flush; 
        cin >> x[i];} 
        while(!((y[i]>=0)&&(y[i]<=b))) { 
        cout << "Try Again y: " << flush; 
        cin >> y[i];} 


        if (s[i] == "S"){ 
          y[i] = (y[i]+1); 
          }else if (s[i] == "J"){ 
           y[i] = (y[i]-1); 
           }else if (s[i] == "V"){ 
             x[i] = (x[i]+1); 
             }else if (s[i] == "Z"){ 
              x[i] = (x[i]-1); 
              } 
        cin >> d; 
        while(!((d>=1)&& (d<=200))) { 
        cout << "Try Again d: " << flush; 
        cin >> d;} 


        for (int counter=0; counter<d; counter++) 
        { 
        cout << genRandom(); 
        } 
        cout << endl; 

      } // koniec for 

      for (i = 0 ; i < n ; i++) 
            { 
             if(!(((x[i]>=0)&&(x[i]<=a)) | ((y[i]>=0)&&(y[i]<=b)))){ 
                cout << x[i] << ' ' << y[i] << ' ' << s[i] << ' ' << "SPADOL" << endl; 
                }else{ 
                cout << x[i] << ' ' << y[i] << ' ' << s[i] << endl; 

                } 

            } 




system("pause"); 

} 

Answer 1

假設數組x，y和s通過new[]和n > 1進行動態分配，你的循環會收回x，y，s第一次，然後將嘗試下一次迭代請閱讀x[i]。

你應該將循環的delete[]外，甚至更好，你應該使用清理自己了自動的，像std::vector容器：

std::vector<int> x; 
std::vector<int> y; 
std::vector<int> s; 

for (i = 0 ; i < n ; i++) { 
    if (
     !((x[i] >= 0) && (x[i] <= a) & 
      (y[i] >= 0) && (y[i] <= b) 
     ) 
    ) { 
     cout << x[i] << ' ' << y[i] << ' ' << s[i] << ' ' << "SPADOL" << endl; 
    } else { 
     cout << x[i] << ' ' << y[i] << ' ' << s[i] << endl; 
    } 
} 

Answer 2

如果您鴕鳥政策用關鍵字「新」分配，你永遠不必調用delete。如果您在堆上分配，則只需要釋放資源。使用標準的lib類，讓他們在內部執行新的/刪除堆。