Pointer: Pointer to Way, Pointer to String Constant and Pointer to Structure

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Image of Pointer to Array

Image of Pointer to Array

Pointer to Array

Consider the following declaration:

int A [ 5].

The name of the array A itself is a pointer which holds the address of zero location (&A [0]).

It is a constant in a program, its value cannot be changed. The following program prints all the values of an array A.

# include < iostream.h >

void main ()

{

int [5] = {20, 35, 25, 22, 27}.

for (int i = 0; i < 5; i + +)

cout << “\n” << A [ i].

}

The output is:

20

35

25

22

27

The above program can be written as pointer notation.

# include < iostream.h >

void main ()

{

int A [5] = {20, 35, 25, 22, 27}

for (int i = 0; i < 5; i + +)

cout << “\n” << *(A + i).

}

At one stage the value of i is 2. Therefore is 2, i.e., two locations from the zero

location. The will print the data stored at that location.

Pointer to String Constant

Consider the following example:

# include < iostream.h >

void main ()

{

char stu1 [] = “work as an array”.

char *stu2 = “work as a pointer”.

cout << stu 1.

cout << stu2; // display both the strings

stu1 ++; / / it is a wrong statement

stu2 + +.

cout << stu2; / / it prints “ork as a pointer”

}stu 1 + + is a wrong statement because stu 1 is a pointer which holds the address of zero location (& stu1 [0]). It is a constant in a program.

Pointer to Structure

Consider the following program

struct student

{

char name [30].

int run.

};

The statement

student st.

declares st as the variable of the structure student.

The statement

student *ptr.

declares a pointer variable ptr to a student.

That data members using ptr can be referred to as

ptr -> name.

ptr -> run.

Another way of referring the data member is

(*ptr).name.

(*ptr). run;

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