Keywords in C


In this article, we will dive deep into the realm of Keywords in C, covering essential concepts, syntax, and practical examples. Whether you are a beginner or an experienced programmer looking to refresh your knowledge, this guide is tailored to cater to all levels of expertise.

Keywords in C: Understanding the Fundamentals

C language incorporates various Keywords that serve as building blocks for writing code. These Keywords have predefined meanings in the language and cannot be used as variable names. Let’s explore some essential Keywords in C:

Sure, here’s the provided information formatted in a table:

autoUsed to declare automatic variables within a block of code.
breakUsed to terminate a loop or switch statement prematurely.
caseUtilized in switch statements to define specific cases.
charRepresents a character data type.
constUsed to define constants that cannot be modified.
continueUsed to skip the current iteration of a loop.
defaultUsed in switch statements to specify a default case.
doUsed to create a do-while loop.
doubleRepresents a double-precision floating-point data type.
elseUsed in conditional statements to define an alternative block of code.
enumUsed to define enumerated data types.
externUsed to declare variables or functions that are defined in other files.
floatRepresents a single-precision floating-point data type.
forUsed to create a for loop.
gotoUsed to transfer control to a labeled statement.
ifUsed to create conditional statements.
intRepresents an integer data type.
longRepresents a long integer data type.
registerUsed to suggest that a variable be stored in a register for faster access.
returnUsed to return a value from a function.
shortRepresents a short integer data type.
signedUsed to declare signed data types.
sizeofUsed to determine the size of a data type or variable.
staticUsed to define static variables with a local scope.
structUsed to define a user-defined data structure.
switchUsed to create a multi-branching decision statement.
typedefUsed to define new data type names.
unsignedUsed to declare unsigned data types.
voidRepresents an empty or no data type.
volatileUsed to indicate that a variable can be modified by external means.

Keywords in C: Examples

Let’s see some examples that showcase the usage and significance of Keywords.

1. The ‘if’ Statement: Making Decisions

The if statement is one of the fundamental control structures in C. It allows us to make decisions based on certain conditions. Consider the following example:

#include <stdio.h>

int main() {
    int number;

    printf("Enter a number: ");
    scanf("%d", &number);

    if (number > 0) {
        printf("The number is positive.\n");
    } else if (number < 0) {
        printf("The number is negative.\n");
    } else {
        printf("The number is zero.\n");

    return 0;

In this example, the if statement checks whether the number is positive, negative, or zero, and it prints the corresponding message accordingly.

2. The ‘for’ Loop: Iterating with Ease

The for loop is a powerful iteration construct in C. It allows us to repeat a block of code a specific number of times. Consider the following example:

#include <stdio.h>

int main() {
    int i;

    for (i = 1; i <= 5; i++) {
        printf("Iteration %d\n", i);

    return 0;

In this example, the for loop prints “Iteration 1” to “Iteration 5” in sequential order.

3. The ‘switch’ Statement: Handling Multiple Cases

The switch statement provides an elegant way to handle multiple cases based on the value of an expression. Consider the following example:

#include <stdio.h>

int main() {
    char grade;

    printf("Enter your grade (A, B, C, D, or F): ");
    scanf(" %c", &grade);

    switch (grade) {
        case 'A':
        case 'B':
        case 'C':
            printf("Well done!\n");
        case 'D':
            printf("You passed, but there's room for improvement.\n");
        case 'F':
            printf("Sorry, you did not pass.\n");
            printf("Invalid grade.\n");

    return 0;

In this example, the switch statement evaluates the value of grade and provides corresponding feedback.

4. The ‘typedef’ Keyword: Creating Custom Data Types

The typedef Keyword allows us to create custom data type names for increased code clarity. Consider the following example:

#include <stdio.h>

typedef struct {
    char name[50];
    int age;
} Person;

int main() {
    Person person1;

    strcpy(, "John Doe");
    person1.age = 30;

    printf("Name: %s\n",;
    printf("Age: %d\n", person1.age);

    return 0;

In this example, we create a custom data type Person using the typedef Keyword to define a structure with a name and age.

FAQs about Keywords in C

  1. What are Keywords in C? Keywords in C are reserved words with predefined meanings that cannot be used as variable names. They play a crucial role in defining the language’s syntax and structure.
  2. How do I declare a constant in C using the ‘const’ Keyword? You can declare a constant in C using the const Keyword before the data type during variable declaration. For example: const int MAX_VALUE = 100;
  3. What is the purpose of the ‘return’ Keyword in C? The return Keyword is used to exit a function and return a value to the calling function. It is especially useful in functions that produce results or computations.
  4. Can I use ‘goto’ to jump between different functions in C? No, the goto statement in C can only jump within the same function. Using goto to jump between different functions can lead to code complexity and is not recommended.
  5. When should I use the ‘volatile’ Keyword in C? The volatile Keyword is used to indicate that a variable’s value may change at any time without any action being taken by the code within the function. It is often used with hardware registers or variables shared between multiple threads.
  6. How can I create a user-defined data type using the ‘typedef’ Keyword? To create a user-defined data type, you can use the typedef Keyword followed by the structure definition. For example: typedef struct { int x, y; } Point;