DSA Strings

Strings Complete Guide in Data Structures

A string is a chain of characters placed one after another. It’s often used to store words, sentences, or any text-based information. In programming, a string acts like a text container, where each letter or symbol has its own position.

Definition

A string is a group of characters like letters, numbers, or symbols, joined together and treated as one single piece of data.

How Strings Work in Memory:

In most languages like C, strings are stored as an array of characters ending with a special character called the null terminator (\0). This special symbol tells the system where the string ends.

Each character in a string sits next to the other in memory, and you can access them just like array elements using their index.

Key Features

• Made up of characters (e.g., 'a', 'b', '1', '#').
• Stored in sequence, like an array.
• Ends with \0 in C-style strings.
• Index starts from 0 for the first character.

Real-Life Analogy:

Imagine alphabet blocks placed in a line to spell a word. Each block is a character, and the whole line of blocks is the string. You can count each block by its position.

Example

#include <stdio.h>  

int main() {     
      char name[] = "Parmi";      

      // Print each character using a loop     
      for(int i = 0; name[i] != '\0'; i++) {         
            printf("Character at index %d is %c\n", i, name[i]);     
       }      

      return 0; 
} 

Output

Character at index 0 is P   
Character at index 1 is a   
Character at index 2 is r   
Character at index 3 is m   
Character at index 4 is i

String Operations

Functions in C for Strings (from )

Advantages of Strings

• Great for handling human-readable data.
• Easy to perform operations like searching or formatting.
• Many built-in tools and functions to work with them.

Limitations

• In C, you must manually handle the null terminator.
• Fixed size unless using dynamic memory.
• Slower than numbers when performing some operations.

When to Use Strings

• To store names, messages, file paths, etc.
• When you need to read or manipulate user text input.
• When you're dealing with alphabets, symbols, or digits in text form.

Bonus – 2 Ways to Declare Strings in C

1. Character Array

char city[10] = "Mumbai";

2. Pointer Method

char *city = "Mumbai";

Both represent strings, but the first lets you modify the characters (if not const), while the second is read-only in many cases.