C Programming Arrays Of Pointers

Last modified by Microchip on 2023/11/09 09:06

Contents

Declaration

An array of pointers is an ordinary array variable whose elements happen to be all pointers.

1 char *p[4];

This creates an array of four pointers to char. The array p[] itself is like any other array. The elements of p[], such as p[1], are pointers to char.

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Initialization

Initializing an element of an array of pointers is just like initializing ordinary pointers, but we must include the array index. This example assigns the address of x to the pointer in the element of the array.

1 p[0] = &x;

 This next example assigns the address of the first character in the string to the pointer in element 0 of the array.

1 p[0] = "My string";

 This example shows how you would populate the array of pointers in the following picture.

Graphic showing how you would populate the array of pointers

1 p[0] = "On";
2 p[1] = "Off";
3 p[2] = "Main";
4 p[3] = "Aux";

This would create the strings in memory and initialize each of the pointers in the array to point to a particular string.

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Dereferencing

To use the value pointed to by a pointer array element, just dereference it like you would an ordinary variable:

1 y = *p[0];

Using *p[0] is the same as using the object it points to, such as x or the string literal "My String" from before.

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Accessing Strings

Example

1 int i = 0;
2 char *str[] = {"Zero", "One", "Two", "Three", "Four", "\0"};
3
4 int main(void)
5 {
6     while(*str[i] != '\0')
7         printf("s\n", str[i++]);
8     while(1);
9 }

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