MemC – See How C Uses Memory

Type C code, click Run or Step, and watch where variables and pointers live in memory

Quick Start (3 steps)

Pick an example below or write your own C code
Click Run to execute all at once, or Step to go line by line
Watch the memory diagram update: Stack (local vars), Heap (malloc), and pointers

Try an example:

Your C code (must have main())

scanf input (comma- or space-separated, e.g. 5 1 2 3 2 2 2)

Controls

No memory to show yet

Click Run or Step to execute your code. The diagram will show where variables live: Stack (local vars), Heap (malloc blocks), and pointers between them.

Output (printf)

No output yet. Use printf("text") or printf("x = %d", x) to print.

What you'll see

Stack — Local variables (e.g. int x = 5) live here. Each function gets its own frame.
Heap — Memory from malloc() or calloc(). You must call free() when done.
Pointers — Variables like int* p store addresses. The arrow (→) shows what they point to.

Learn Memory Concepts

Stack vs Heap Pointers in C malloc vs calloc Use-After-Free Double-Free Memory Leaks

Example Programs

Simple Stack

int and pointer basics