POINTER
WHAT IS POINTER?
In computer programming, a pointer is a variable that stores the memory address of another variable. Pointers allow for more efficient and flexible memory management by providing a way to indirectly access and manipulate data. Instead of directly working with the data itself, you work with the memory address where the data is stored.
Pointers are commonly used in low-level programming languages like C and C++, where direct memory manipulation is required. However, they are also present in other programming languages, albeit often hidden or abstracted away.
Here's a simple example in C to illustrate the concept of pointers:
#include <stdio.h>
int main() { int num = 42; // Declare and initialize an integer variable int *ptr; // Declare a pointer variable ptr = # // Assign the address of 'num' to the pointer variable printf("Value of num: %d\n", num); // Output: Value of num: 42 printf("Address of num: %p\n", &num); // Output: Address of num: 0x7ffc8b65e39c printf("Value of ptr: %p\n", ptr); // Output: Value of ptr: 0x7ffc8b65e39c printf("Value pointed by ptr: %d\n", *ptr); // Output: Value pointed by ptr: 42 return 0; }
In this example, we declare an integer variable num and initialize it with the value 42. We also declare a pointer variable ptr that can store the memory address of an integer. Using the & operator, we assign the address of num to ptr. We can then use the * operator to access the value stored at the memory location pointed by ptr. So, *ptr refers to the value of num.
Pointers are powerful tools, but they require careful handling to avoid issues like null pointers, memory leaks, and improper dereferencing. Modern high-level programming languages often abstract away direct pointer manipulation for safety and ease of use.
what is array?
An array is a data structure that stores a fixed-size sequence of elements of the same type. It provides a way to organize and access multiple related values under a single name. Each element in an array is identified by its index or position within the array, starting from zero.
Arrays are commonly used in programming to store collections of data such as a list of numbers, a series of characters, or any other type of homogeneous data. They offer efficient random access to elements, which means you can access any element in constant time if you know its index
Here's an example of an array in C:
#include <stdio.h> int main() { // Declare an array of integers int numbers[5]; // Assign values to the array elements numbers[0] = 10; numbers[1] = 20; numbers[2] = 30; numbers[3] = 40; numbers[4] = 50; // Access and print array elements printf("%d\n", numbers[0]); // Output: 10 printf("%d\n", numbers[2]); // Output: 30 printf("%d\n", numbers[4]); // Output: 50 return 0; }
numbers of size 5, capable of holding 5 integers. We then assign values to each element using the square bracket notation and the index. Finally, we access and print individual elements by specifying the array name followed by the index inside square brackets.