Why C Still Matters in 2025

Despite being over 50 years old, C is still the backbone of many systems around us. It powers your operating system, embedded devices in your home, gaming consoles, and even IoT gadgets. This guide explores how industries use C and includes practical code examples you can try today.

1. C in Operating System Development

Real-World Insight

Operating systems like Linux, UNIX, and even parts of Windows are mostly written in C. Why? Because C offers:

• Low-level memory access
• Efficient performance
• Portability across platforms

Step-by-Step Example: Build a Simple Command Line Shell

Let’s simulate a basic shell that takes user input and runs it.

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

int main() {
    char command[100];

    while (1) {
        printf("MiniShell> ");
        fgets(command, sizeof(command), stdin);
        system(command); // Executes the command in terminal
    }

    return 0;
}

This kind of interaction forms the basis of real shell environments used in OS terminals.

2. C in Embedded Systems

Real-World Insight

C is the go-to language for programming microcontrollers and embedded chips. It runs everything from your microwave oven to your car’s airbag system.

Why C?

• Fast execution on low-power hardware
• Precise hardware control via registers
• Minimal memory footprint

Step-by-Step Example: LED Blink Simulation

#include <stdio.h>
#include <unistd.h>  // for sleep()

int main() {
    while (1) {
        printf("LED ON\n");
        sleep(1); // wait 1 second
        printf("LED OFF\n");
        sleep(1);
    }

    return 0;
}

In real embedded devices, this would control a GPIO pin to turn an LED on/off.

3. C in Game Engine Development

Real-World Insight

Classic games like Doom, Quake, and many early console games were written in C. Even modern engines use C or C++ at the core.

Why C?

• Close control over memory = faster performance
• Ideal for low-level rendering and physics
• Integrates well with graphics APIs like OpenGL

Step-by-Step Example: Console Game Menu

#include <stdio.h>

int main() {
    int choice;

    printf("=== Game Menu ===\n");
    printf("1. Start Game\n2. Load Game\n3. Exit\n");
    printf("Enter choice: ");
    scanf("%d", &choice);

    switch (choice) {
        case 1: printf("Game Starting...\n"); break;
        case 2: printf("Loading Save Data...\n"); break;
        case 3: printf("Goodbye!\n"); break;
        default: printf("Invalid option.\n");
    }

    return 0;
}

4. C in IoT (Internet of Things)

Real-World Insight

C is commonly used in IoT sensors and actuators because it runs directly on hardware with tight constraints on power and memory.

Why C?

• Runs on microcontrollers like Arduino or STM32
• Offers real-time performance
• Easy to integrate with communication protocols (e.g., I2C, SPI)

Step-by-Step Example: Simulate Temperature Sensor

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

int main() {
    srand(time(0));

    for (int i = 0; i < 5; i++) {
        int temperature = 18 + rand() % 10;  // random temp between 18–27°C
        printf("Temperature Reading %d: %d°C\n", i + 1, temperature);
    }

    return 0;
}

This mimics a basic IoT sensor sending data periodically.

Mini Project: Simulated IoT Temperature Alert System in C

Project Objective

Create a simple C program that reads simulated temperature data and alerts if the temperature exceeds a set limit.

Key Features

• Random temperature generation
• Threshold alert
• Data stored in an array

Full Code

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

#define MAX_READINGS 10
#define TEMP_LIMIT 28

int main() {
    int temperatures[MAX_READINGS];
    srand(time(0));

    printf("IoT Temperature Monitoring System\n");
    printf("----------------------------------\n");

    for (int i = 0; i < MAX_READINGS; i++) {
        temperatures[i] = 20 + rand() % 15;
        printf("Reading %d: %d°C", i + 1, temperatures[i]);

        if (temperatures[i] > TEMP_LIMIT) {
            printf(" -> ALERT: High Temp!\n");
        } else {
            printf("\n");
        }
    }

    return 0;
}

Summary Table: C in Different Industries

Interview Questions

Google

Q: Why is C used for OS kernels?
Because C allows direct memory and hardware access, which is essential for system-level programming.

TCS

Q: What makes C suitable for embedded systems?
C is fast, reliable, and efficient on devices with limited memory and processing power.

Infosys

Q: Can C be used for IoT systems?
Yes. C supports real-time processing and runs well on microcontrollers used in IoT.

IBM

Q: How does C enhance game engine performance?
It allows precise control over memory and CPU, helping game engines run efficiently.

Wipro

Q: Give an industrial automation example using C.
C is used to program control systems like PLCs that handle conveyor belts and temperature sensors in factories.

Final Thoughts

C continues to dominate in critical areas where performance, efficiency, and control matter most. Whether you’re building an OS, an IoT system, or an embedded product, learning C gives you a powerful edge in the tech industry.