What is C - Practice Questions & Exercises

Challenge - 5 Problems

🧠 Conceptual

intermediate

What is the primary use of the C programming language?

Which of the following best describes the main purpose of the C programming language?

A A scripting language used for automating tasks.

B A high-level language mainly used for web development.

C A low-level language used for system programming and embedded systems.

D A language designed exclusively for database management.

💡 Hint

Think about what kind of programs need direct hardware access and efficiency.

C is a low-level language that provides control over hardware and memory, making it ideal for system programming and embedded systems.

❓ Predict Output

intermediate

Output of a simple C program

What is the output of the following C program?

C

#include <stdio.h>

int main() {
    int a = 5, b = 3;
    printf("%d\n", a + b);
    return 0;
}

A 8

B 53

C 0

D Error: invalid syntax

💡 Hint

Remember that the + operator adds numbers, not concatenates them.

The program adds 5 and 3, printing 8.

❓ Predict Output

advanced

What is the output of pointer manipulation?

What will this C program print?

C

#include <stdio.h>

int main() {
    int x = 10;
    int *p = &x;
    *p = 20;
    printf("%d\n", x);
    return 0;
}

A Compilation error

B Address of x

C 10

D 20

💡 Hint

Changing the value pointed to by p changes x.

The pointer p points to x, so *p = 20 changes x to 20.

🔧 Debug

advanced

Identify the error in this C code snippet

What error will this C code produce?

C

#include <stdio.h>

int main() {
    int arr[3] = {1, 2, 3};
    printf("%d\n", arr[3]);
    return 0;
}

A Undefined behavior (accessing out of bounds)

B Compilation error

C Prints 3

D Prints 0

💡 Hint

Array indices start at 0 and go up to size-1.

Accessing arr[3] is out of bounds and causes undefined behavior.

🧠 Conceptual

expert

Why is C considered a 'portable' language?

Which reason best explains why C is called a portable programming language?

A Because C code can run without any changes on all hardware architectures.

B Because C compilers exist for many platforms, allowing code to be recompiled easily.

C Because C programs do not use any hardware-specific features.

D Because C automatically translates code to machine language for any device.

💡 Hint

Think about how code moves between different computers.

C is portable because many compilers exist for different systems, so source code can be recompiled on each platform.