Implement malloc on the stack

Implementing a stack-based memory allocator in C++

This medium-difficulty coding problem tests your ability to manage memory layout, alignment, and pointer arithmetic—core skills for systems programming and performance-critical code. It appears in interviews at firms where low-latency allocation matters, such as high-frequency trading shops and embedded systems teams.

The challenge is to build a simple but correct allocator that lives entirely on the stack (no heap or static storage), respects alignment constraints, and tracks available space. Success requires understanding how to compute aligned offsets, detect exhaustion, and support bulk reset. Interviewers typically follow up by asking about alignment padding, how you'd handle alignment requests larger than the buffer, or how you'd extend the design to support deallocation of individual blocks.

• Pointer arithmetic and byte-level memory layout
• Alignment computation using bit masks and ceiling division
• Bump-pointer allocation strategy and fragmentation
• Template instantiation with compile-time capacity
• Edge cases: zero-size requests, alignment larger than remaining space