Core Concept Mastery • DSA Module
A string is a sequence of characters stored in memory, like beads on a necklace. Each character sits in its own memory slot, arranged in order to form words and sentences.
Think of a string like a pearl necklace. Each pearl (character) is connected in order. The clasp (\0) marks the end. If you remove the clasp, you can't tell where the necklace ends!
Strings are just Arrays of Characters ending with a \0 (Null Character)!
Base Address (1000) + Offset = Character Address
Length = 5, Memory Size = 6 (includes \\0)
1// C/C++2char str[] = "HELLO";3// Memory: {'H', 'E', 'L', 'L', 'O', '\0'}45// JavaScript/Python6let str = "HELLO";7// Same concept, but language handles \0 automatically89// Accessing characters10str[0] // 'H' (first character)11str[4] // 'O' (fifth character)12str[5] // '\0' (null terminator)
Let's build this from scratch, no prior knowledge needed.
The Pearl Necklace Analogy
Imagine a beautiful pearl necklace. Each pearl is a character — 'H', 'e', 'l', 'l', 'o'. They're strung together in a specific order. Change the order, and you get a different word! "Hello" becomes "olleh" if reversed.
How Strings Live in Memory
Strings are stored as arrays of characters in contiguous (touching) memory locations. Just like an apartment building where each room is numbered sequentially, each character has an address. The first character is at index 0, the second at index 1, and so on.
The Hidden Clasp — Null Terminator
Here's the crucial part: strings end with a special invisible character called the null terminator, written as \0. This tells the computer "stop reading here!" Without it, the computer would keep reading memory past your string, showing garbage data.
Why This Matters
The Memory Layout
For the string "HELLO", memory looks like this:
The length is 5 (characters before \0), but it takes 6 bytes in memory (including \0).
Strings are everywhere in programming — usernames, passwords, file paths, messages, user input. Understanding how strings work in memory helps you write efficient code and avoid common bugs like buffer overflows.
"How is a string stored in memory?"
As an array of characters in contiguous memory, ending with a null terminator (\0). Each character occupies one byte, and the string length is the number of characters before \0.