#28: Dynamic Memory Allocation in C | C Programming for Beginners

#28: Dynamic Memory Allocation in C | C Programming for Beginners

In this video, we will learn about dynamic memory allocation in C programming. More specifically, we will learn to allocate and destroy memory addresses while running the C program. Dynamic memory allocation allows us to allocate memory dynamically. C provides 3 major functions to perform dynamic memory allocation: malloc(), realloc(), and free(). We will now learn about each one of them with examples.

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Resources:

Timestamps:
01:13 - malloc() function
02:56 - free() function
08:11 - realloc() function
11:04 - Programming Task
11:50- Quiz
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[programizstudios]

🔥Finding it Damn Hard to Understand C Programming?
Learn to code—the right way—with interactive lessons, quizzes & challenges. Build a strong programming base; it's IMPORTANT!

[LucasFCunha]

"Dynamic memory allocation allows us to allocate memory dynamically" 10/10 explanation.

[CakeInvasion]

The best for beginners is to read a complete tutorial. Without skipping important steps. It's important to UNDERSTAND how things work, not just make them work

[nickralston]

Great videos, Computer science can get really confusing at parts, especially when you go from java/python to c, currently taking a course in college, and these videos have helped me greatly

[irfanquader]

Your website has helped me a lot in my coding journey, thanks a lot for your contribution to the community.

[guidoxenofonte]

i have a test on tuesday about this subject and you helped me a lot on learning it. i really hope that more and more people will be helped by this and the other videos of yours. God bless y'all and thx for the great content :D

[Tallaab]

good explanation; B for the question asked last.

[videoventures]

You are doing an amazing job . I have learned alot

[programizstudios]

[ Programiz Quiz ]

Q. What is the correct way to allocate memory to store 12 double data?
a. malloc(20 * double)
b. (double*) malloc(12 * sizeof(double))
c. (double) malloc(20 * sizeof(double))
d. (double*) malloc( sizeof(20 * int))

[programizstudios]

Q. What is the correct way to allocate memory to store 12 double data?

A. malloc(20 * double)
B. (double*) malloc(12 * sizeof(double))
C. (double) malloc(20 * sizeof(double))
D. (double*) malloc( sizeof(20 * int))

[yogithabale]

mam, we should also use #include <stdlib.h> at the starting of code then only we are able to run the code

[plankalkulcompiler]

Thanks for the video, it helped a lot!

[brettchallice]

There's an error @ 8:15. "In our previous example we have allocated 400 bytes of memory to store 4 integer values." Each integer is four bytes, and thus you're allocating for four integers (4 bytes x 4 values) = 16 bytes of allocated memory.

[errorhostnotfound]

I'm getting a warning for ptr = realloc(ptr, n * sizeof(int)); saying that realloc could return NULL, which "will cause the original memory block to be leaked", any know how to fix this?

[tteokmember]

#include <stdio.h>
#include <stdlib.h>

int main() {

int n, i, *ages;

n = 4;

ages = (int*) malloc(n * sizeof(int));

if(ages == NULL){
printf("ERROR! Memory not allocated\n");
return 0;
}

printf("Input %d values: \n", n);
for(i = 0; i < n; i++){
scanf("%d", ages + i);
}

printf("Initial array elements: \n");
for(i = 0; i<n; i++){
printf("%d ", *(ages + i));
}

n = 6;

ages = realloc(ages, n * sizeof(int));

ages[4]=32;
ages[5]=59;

printf("\nFinal array elements: \n");
for(i = 0; i<n; i++){
printf("%d ", *(ages + i));
}

free(ages);

return 0;
}

[TheHeraldOfSpring]

ENGAGEMENT ! ENGAGEMENT ! ENGAGEMENT ! ENGAGEMENT ! ENGAGEMENT ! ENGAGEMENT ! ENGAGEMENT ! ENGAGEMENT !

[countrysideshowyaigrock]

#include <stdio.h>

int main() {

int quantity = 4;

int* ages;

ages = (int*)malloc(quantity * sizeof(int));

if (ages == NULL) {
printf("Memory can`t be allocated");
return 0;
}
printf("Enter input values:\n");
for (int i = 0; i < quantity; ++i) {
scanf("%d", ages + i);
}
printf("Input values:\n");
for (int i = 0; i < quantity; ++i) {
printf("%d\n", *(ages + i));
}

quantity = 6;

ages = realloc (ages, quantity * sizeof(int));

ages[4] = 32;
ages[5] = 59;

printf("We adding new values:\n");
for (int i = 0; i < quantity; ++i) {
printf("%d\n", *(ages + i));
}

free(ages);

return 0;
}

[onic]

Option B : (double*) malloc(12 * sizeof(double))



#include <stdio.h>

int main() {

int n = 4, i;
int* ages;

ages = (int*) malloc(n * sizeof(int));

if(ages == NULL) {
printf("Memmory Cannot Allocated");
return 0;
}

printf("Enter Four Ages:\n");

for(i = 0; i < n; i++) {
scanf("%d", ages + i);
}

printf("Initial Array Elements: \n");
for(i = 0; i < n; i++) {
printf("%d ", *(ages + i));

}

n = 6;

ages = realloc(ages, n * sizeof(int));

ages[4] = 32;
ages[5] = 59;

printf("\nFinal Array Elements: \n");
for(i = 0; i<n; i++) {
printf("%d ", *(ages + i));
}

free(ages);

return 0;
}

[laylalilly]

When i run the realloc() code in visual studio code it returns an error as its expecting a void data type yet the malloc() worked.
Can anyone 'point' me in the right direction?

Thanks

int *ptr, i, n1, n2; 
ptr = (int*) malloc(n1 * sizeof(int));
ptr = realloc(ptr, n2 * sizeof(int)); // error expecting void type in ptr ?

[sandeepvarma]

programming task:
#include<stdio.h>
#include<stdlib.h>
int main(){
int n=4;
int* ages;
if(ages==NULL){
printf("memory is not allocated");
}

printf("enter input values: ");
for(int i=0;i<n;i++){
scanf("%p", (ages+i));
}
n=6;
ages=realloc(ages, n*sizeof(int));
ages[4]=32;
ages[5]=59;
printf("\nnewely assigned values: ");
for(int i=0;i<n;i++){
printf("\n%d", *(ages+i));
}
return 0;
}
quiz:option b is correct