Character Set & Tokens in C

 

💻 Character Set & Tokens in C (Easy Explanation)

When you write a C program, it is made using characters and tokens. Let’s understand both step-by-step 👇

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🔹 1. Character Set in C

A character set means all the valid characters that can be used to write a C program.

✅ Types of Characters

🔸 1. Alphabets (Letters)

• A to Z (uppercase)
• a to z (lowercase)

👉 Example: a, B, x, Z

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🔸 2. Digits (Numbers)

• 0 to 9

👉 Example: 0, 5, 9

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🔸 3. Special Symbols

+  -  *  /  %  =  <  >  !  &  |  ^  ~
( ) { } [ ] ; , . # _ " '

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🔸 4. White Spaces

• Space
• Tab
• New line

👉 Used to make code readable

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🔹 2. Tokens in C

Tokens are the smallest units (building blocks) of a C program.

👉 Example:

int a = 10;

Tokens are: int, a, =, 10, ;

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🔹 Types of Tokens

🔸 1. Keywords 🔑

• Reserved words (special meaning)
• Cannot be used as variable names

👉 Examples:
int, float, if, else, return

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🔸 2. Identifiers 🏷️

• Names given to variables, functions

👉 Examples:
a, sum, totalMarks

👉 Rules:

• Cannot start with number
• No spaces
• No special symbols (except _)

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🔸 3. Constants 🔢

• Fixed values (do not change)

👉 Examples:
10, 3.14, 'A'

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🔸 4. Strings 🧵

• Group of characters inside double quotes

👉 Example:
"Hello"

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🔸 5. Operators ➕

• Used to perform operations

👉 Examples:
+, -, *, /, =

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🔸 6. Special Symbols 🔣

• Symbols like ;, {}, ()

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🔹 Simple Example Breakdown 🧠

#include <stdio.h>

int main() {
    int a = 5;
    printf("Hello");
}

👉 Tokens:

• Keywords: int
• Identifiers: main, a, printf
• Constants: 5
• String: "Hello"
• Symbols: () { } ;

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🔹 Summary 📝

• Character Set = All valid characters
• Tokens = Smallest parts of program