Objective-C 指针数组

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  指针数组

  在理解指针数组的概念之前，让我们考虑以下示例，该示例使用3个整数的数组-

  
  #import <Foundation/Foundation.h>
   
  const int MAX = 3;
   
  int main () {
     int  var[] = {10, 100, 200};
     int i;
   
     for (i = 0; i < MAX; i++) {
        NSLog(@"Value of var[%d] = %d\n", i, var[i] );
     }
     return 0;
  }
  

  编译并执行上述代码后，将产生以下结果-

  
  2020-08-08 09:36:45.574 test[5172:9900] Value of var[0] = 10
  2020-08-08 09:36:45.581 test[5172:9900] Value of var[1] = 100
  2020-08-08 09:36:45.581 test[5172:9900] Value of var[2] = 200
  

  在某些情况下，我们需要维护一个数组，该数组可以存储指向int或char或任何其他可用数据类型的指针。以下是指向整数的指针数组的声明-

  
  int *ptr[MAX];
  

  这将ptr声明为MAX个整数指针的数组。因此，ptr中的每个元素现在都拥有一个指向int值的指针。以下示例使用三个整数，这些整数将按如下方式存储在指针数组中：

  
  #import <Foundation/Foundation.h>
  
  const int MAX = 3;
   
  int main () {
     int  var[] = {10, 100, 200};
     int i, *ptr[MAX];
   
     for ( i = 0; i < MAX; i++) {
        ptr[i] = &var[i];   /* assign the address of integer. */
     }
     for ( i = 0; i < MAX; i++) {
        NSLog(@"Value of var[%d] = %d\n", i, *ptr[i] );
     }
     return 0;
  }
  

  
  2020-08-08 09:43:11.193 test[6272:5204] Value of var[0] = 10
  2020-08-08 09:43:11.200 test[6272:5204] Value of var[1] = 100
  2020-08-08 09:43:11.200 test[6272:5204] Value of var[2] = 200
  

  您还可以使用指向字符的指针数组来存储字符串列表，如下所示：

  
  #import <Foundation/Foundation.h>
  
  const int MAX = 4;
   
  int main () {
     char *names[] = {"Zara Ali", "Hina Ali", "Nuha Ali", "Sara Ali",};
     int i = 0;
     for ( i = 0; i < MAX; i++) {
        NSLog(@"Value of names[%d] = %s\n", i, names[i] );
     }
     
     return 0;
  }
  

  
  2020-08-08 09:46:37.647 test[5568:884] Value of names[0] = Zara Ali
  2020-08-08 09:46:37.654 test[5568:884] Value of names[1] = Hina Ali
  2020-08-08 09:46:37.654 test[5568:884] Value of names[2] = Nuha Ali
  2020-08-08 09:46:37.654 test[5568:884] Value of names[3] = Sara Ali