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An In-Depth Understanding of Memory and Pointers in C

Memory

Explore the basics of memory in C programming by understanding how variables are stored in memory, the difference between volatile and non-volatile memory, and how binary representation works. This lesson helps you gain an intuitive understanding of memory structure, bits, bytes, and variable storage essential for effective coding in C.

We'll cover the following...

Introduction

At one point or another, we came across variables. They’re our go-to tool for:

  • Storing and processing information
  • Doing calculations and producing an output

To illustrate this, consider a scenario where we want to read the first name, age, and email address of a user, each separated with a space in a single line. Our code will display the entered data and store it in a file (user_data.txt) for later use.

Don’t worry if you’re not familiar with working with files in C! It is just an example for us to analyze.

C
#include <stdio.h>
int main()
{
    char inputBuffer[72];
    char name[32];
    int age;
    char emailAddress[32];
    fgets(inputBuffer, 72, stdin);
    sscanf(inputBuffer, "%s %d %s", name, &age, emailAddress);
    printf("Received from user: [%s] [%d] [%s]\n", name, age, emailAddress);
    FILE *filePtr = fopen("output/user_data.txt", "a");
    if (filePtr != NULL)
    {
        fprintf(filePtr, "%s %d %s\n", name, age, emailAddress);
        fclose(filePtr);
        printf("Saved user data to file!\n");
    }
    else
    {
        printf("Could not open file!\n");
    }
    return 0;
}
Did you find this helpful?

Let’s give it a try! Type something like Mark 22 mark123@gmail.com (without the quotes). After running the code, we’ll be able to download the generated file and see the output.

Asking questions

Now, let’s ask a few questions about this simple code:

1.

We used variables like name, age, and emailAddress(lines 6, 7, and 8 highlighted in the code above) to store data in the program. Where are the variables stored?

Show Answer
1 / 2

The answer to both the questions is inside the memory!

Remember when we were in school trying to learn a new subject. We were reading our notes or textbook and attempting to memorize them. Our brain stores the information somewhere for later use.

A computer does the same thing. It takes the information we give and uses ...