C++練習定義類型

Question

我一直在做一些練習從一本書，我想知道如果你能告訴我，如果他們是正確的。這不是功課，我只是在練習。我評論了我應該做的，我的實際代碼

#include <iostream> 
#include <string> 
using namespace std; 

//int main(){} 

// 1 
char *ptc;        //pointer to char 
int Array[10];       //array of 10 ints 
int (&arrayRef)[10] = Array;   //ref to Array 
string *pts;       //pointer to a array of strings 
char** pptc;       //pointer to pointer to char 
const int const_int =0;     //constant integer 
const int* cpti;      //constant pointer to a integer 
int const* ptci;      //pointer to constant integer 

// 3 
typedef unsigned char u_char;   //u_char = 2; 
typedef const unsigned char c_u_char; //c_u_char = 2; 
typedef int* pti;      //pti = &Array[0]; 
typedef char** tppc;     //ttpc = ptc; ? 
typedef char *ptaoc;     //pointer to array of char 
typedef int* pta;      //array of 7 pointers to int ? 
pta myPTA = (int *)calloc(7, sizeof(int)); 
typedef int** pta2;      //pointer to an array of 7 pointers to int ? 
pta2 mypta2 = &myPTA; 
/* ??? */        //array of 8 arrays of 7 pointers to int 

// 4 
void swap1(int *p, int *q)    //this should swap the values of p & q but the last line isn't working q = &aux?? 
{ 
    int aux;       //int a = 5, b = 8; 
             //swap1(&a, &b); 
    aux = *p; 
    *p = *q;       //it returns 8 and 8 
    q = &aux; 
} 

int main() 
{ 
} 

編輯： 的問題是：我如何申報的7個8個指針數組的數組爲int

這是正確的？

typedef char** tppc;     //ttpc = ptc; ? 
typedef char *ptaoc;     //pointer to array of char 
typedef int* pta;      //array of 7 pointers to int ? 
pta myPTA = (int *)calloc(7, sizeof(int)); 
typedef int** pta2;      //pointer to an array of 7 pointers to int ? 
pta2 mypta2 = &myPTA; 

爲什麼不是功能swap1的工作？

Answer 1

廣告1）

要聲明的7個指針的8個陣列的DECLARE陣列爲int你必須鍵入以下內容：

int* arr[8][7]; 

廣告2）

你的交換函數不工作，因爲您正在設置指向函數局部變量的指針。

一個小的變化，一切都應該很好地工作：

void swap1(int *p, int *q)    //this should swap the values of p & q but the last line isn't working q = &aux?? 
{ 
    int aux;       //int a = 5, b = 8; 
             //swap1(&a, &b); 
    aux = *p; 
    *p = *q;       //it returns 8 and 8 
    *q = aux; // <-- notice change here! 
}