Question

In this lab, we want to get some practice with pointers -- specifically, the basic syntax of declaring them, storing memory addresses into them, dereferencing them, and seeing how they work with pointer arithmetic in the context of built-in, C-style arrays.

Unless specified otherwise, you can use any valid variable names you wish. The requirements for this program are as follows:

Part A

1. Declare a pointer-to-int, initialized to nullptr.
2. Declare an int variable, initialized to some value of your choice.
3. Assign the address of the int variable into the pointer-to-int.
4. In a cout statement, dereference the pointer to display the value stored in the int variable.

Part B

1. Declare a double variable, initialized to some value of your choice.
2. Declare a pointer-to-double, initialized with the address of the double variable.
3. In a cout statement, dereference the pointer to display the value stored in the double variable.

Part C

1. Declare a built-in, C-style array of chars, initialized to hold at least 10 char values using list-initialization syntax.
2. Declare a pointer-to-char, initialized to point to the first element in your array. Although there are two ways to do this, please use the version with only the name of the array itself (i.e., if your array is named myCharArray, don’t use &myCharArray[0]).
3. In four cout statements, display the value stored in the fifth element of the array using the each of the following notations:
   • array subscript notation
   • pointer/offset notation with the built-in array name
   • pointer subscript notation
   • pointer/offset notation with the pointer name

Sample output is provided below. Note that your output will vary, depending on the values you chose to store... the important thing here is the syntax you used to produce the output.

Value stored in x: 121

Value stored in y: 2.7

Using array subscript notation: p

Using pointer offset notation with array name: p

Using pointer subscript notation: p

Using pointer offset notation with pointer name: p

C++

Answer 1

#include<stdio.h>  
int main(){    
    // Part A
    int *p1; 
    int x=121;       
    p1=&x;    
    printf("Value stored in x %d \n",*p1);
    
    // Part B
    double y=2.7;
    double *p2=&y;
    printf("Value stored in y %f \n",*p2);
    
    // Part C
    char z[]={'a', 'v', 'g', 'x', 'p'};
    char *p3=z;
    printf("Using array subscript notation: %c \n",z[4]);
    printf("Using pointer offset notation with array name: %c \n",*(p3+4));
    printf("Using pointer subscript notation: %c \n",p3[4]);
    printf("Using pointer offset notation with pointer name: %c \n",*(z+4));
    return 0; 
}