C User Input

1. Basic Input Functions

In C, user input is mainly taken using:

1. scanf() → Reads formatted input

2. getchar() → Reads a single character

3. gets() → Reads a string (unsafe, avoid using)

4. fgets() → Reads a string safely

2. Using scanf()

• scanf() is used for numbers, characters, and strings.

• Always provide address of the variable using & for non-string types.

Syntax:

Example 1: Read an integer

Input/Output:

Example 2: Read a float

Input/Output:

Example 3: Read a character

Input/Output:

Tip: Space before %c in scanf ignores previous newline character.

Example 4: Read a string

Input/Output:

Note: scanf("%s") cannot read strings with spaces.

3. Using fgets() for Strings with Spaces

Input/Output:

Use strcspn(name, "\n") to remove the newline if needed:

4. Using getchar() to Read Single Character

Input/Output:

5. Key Points About User Input

1. Use scanf for formatted input (numbers, strings without spaces, chars).

2. Use fgets for strings with spaces.

3. Use getchar for single characters.

4. Always check array size for strings to avoid buffer overflow.

5. Use & with variables except strings, because strings are already pointers.