C Programming Cheatsheet

Quick reference for commonly used C functions and syntax. Use this page when you need fast recall while coding.

Input / Output

• printf() – Print output
• scanf() – Take input
• puts() – Print string with newline
• gets() – Read string

Memory Management

• malloc() – Allocate memory
• calloc() – Allocate and initialize memory
• realloc() – Resize memory block
• free() – Release memory

Loops

• for – Fixed iteration
• while – Condition loop
• do while – Runs at least once

Strings

• strlen() – Length of string
• strcpy() – Copy string
• strcmp() – Compare strings
• strcat() – Concatenate strings