Memory allocation is a crucial aspect of programming.
There are two ways
It's done at a compile-time.
The size of the memory is determined before the program is executed.
EDUCATION
#include <stdio.h>
int main() {
int x = 10; // Variable x is allocated on the stack
// ...
return 0;
}
Variables declared within a function are typically allocated on the stack.
The memory is automatically released when the function exits.
It's done at runtime and allows for flexible memory management.
Performed using the functions malloc, calloc, realloc, and free from the <stdlib.h> library.
Functions
Description
Example
malloc
Memory Allocation: Allocates a block of memory for an array of 5 integers.
int *dynamicArray = (int *)malloc(5 * sizeof(int));
calloc
Contiguous Memory Allocation: Allocates contiguous block of memory for an array of 5 integers and initializes them to zero.
int *dynamicArray = (int *)calloc(5, sizeof(int));
realloc
Reallocation: Changes the size of the previously allocated memory block (here, resizing to space for 10 integers).
dynamicArray = (int *)realloc(dynamicArray, 10 * sizeof(int));
free
Memory Deallocation: Releases the memory allocated by malloc, calloc, or realloc
free(dynamicArray);
#include <stdio.h>
#include <stdlib.h>
int main() {
// Dynamic memory allocation for an integer
int *dynamicInt = (int *)malloc(sizeof(int));
*dynamicInt = 42;
printf("Dynamic Integer: %d\n", *dynamicInt);
// Dynamic memory allocation for an array of integers
int *dynamicArray = (int *)malloc(5 * sizeof(int));
for (int i = 0; i < 5; i++) {
dynamicArray[i] = i * 10;
}
printf("Dynamic Array: ");
for (int i = 0; i < 5; i++) {
printf("%d ", dynamicArray[i]);
}
printf("\n");
// Freeing dynamically allocated memory
free(dynamicInt);
free(dynamicArray);
return 0;
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