86. Circular Buffer Read

#include <stdio.h>

typedef struct {
    int buffer[10];
    int head;
    int tail;
    int count;
    int capacity;
} CircularBuffer;

void read_bytes(CircularBuffer *cb, int n) {
    // Print values from buffer up to n
    // if less items then n, then print the rest as NULL
    char* seperator = "";
    while (n > 0) {
        if (cb->count <= 0) {
            printf("%sNULL", seperator);
        } else {
            printf("%s%d", seperator, cb->buffer[cb->tail]);
            cb->tail = (cb->tail + 1) % cb->capacity;
            cb->count--;
        }
        seperator = " ";
        // Increment tail with modulo
        // Decrase count
        n--;
    }
    printf("\n");
    printf("Tail: %d\n", cb->tail);
    return;
}

int main() {
    CircularBuffer cb = {
        .buffer = {10, 20, 30, 40, 50, 60, 70, 80, 90, 100},
        .head = 3,
        .tail = 7,
        .count = 6,
        .capacity = 10
    };

    int n;
    scanf("%d", &n);
    read_bytes(&cb, n);

    return 0;
}