Single-byte checksum of a payload
Many lightweight protocols use a one-byte checksum: just the sum of all bytes modulo 256.
- Each element in the payload is a byte value (0–255).
- The checksum is the sum of all bytes modulo 256.
- An empty payload has a checksum of 0.
checksumByte(payload: list<int>) → int
C++ needs a compiler and Drill does not host one yet, so this page is the reference rather than an exercise: the problem, worked examples, and the solution in full. To type it out, the same problem runs in Python.
Where you start
int checksumByte(std::vector<int> payload) {
}Worked examples
| Call | Result |
|---|---|
checksumByte(std::vector<int>{1, 2, 3}) | 6 |
checksumByte(std::vector<int>{255, 1}) | 0 |
checksumByte(std::vector<int>{}) | 0 |
checksumByte(std::vector<int>{128, 128}) | 0 |
Hint
Add every element, then take the remainder when divided by 256.
Reference solution in C++
int checksumByte(std::vector<int> payload) {
int sum = 0;
for (int b : payload) sum += b;
return sum % 256;
}