Strings: The Hidden Reality

Unlike modern languages like Java or Python, C does not have a native "String" data type. Instead, a string is simply an array of characters ending with a special marker: the Null Character (\0).

Why the Null Character?

Imagine the computer's memory is a long street. A string is a row of houses. The \0 is the "End of Street" sign. When you ask C to print a string, it starts at the first character and keeps reading until it sees that zero. If you forget the null character, C will keep reading memory past your array, printing random junk until it eventually crashes.

Initialization

char name[] = "Rahul"; // C adds `\0` automatically at the end.
char city[6] = {'D', 'e', 'l', 'h', 'i', '\0'}; // Manual initialization.

The <string.h> Library

This is your toolkit for handling text. You must include it at the top of your file.

• strlen(str): Returns the number of characters (not counting the null).
• strcpy(dest, src): Copies the content of one string into another.
• strcat(s1, s2): Appends (joins) s2 to the end of s1.
• strcmp(s1, s2): Compares two strings. Returns 0 if they are identical.

Comparing Strings (The Common Trap)

if (str1 == str2) // WRONG! This compares the memory addresses, not the text.
if (strcmp(str1, str2) == 0) // CORRECT! This compares the actual characters.

Reading Strings with Spaces

scanf("%s", ...) stops at the very first space. To read a full line like "Siksha Sarovar", you should use fgets().

char buffer[100];
fgets(buffer, 100, stdin);

Memory Calculation

The word "C is Fun" has 8 characters. To store it as a string, you need an array of at least 9 bytes (8 for text + 1 for \0).

Always ensure your array is big enough! Writing a 20-character name into a 10-character array will cause a "Buffer Overflow," which is the source of many famous security vulnerabilities.