Circular Buffer Read

Approach and Code

#include <stdio.h>
/*
Function reqs:
- Read and print n values from the buffer
- If fewer than n values then print NULL in place of missing ones
- Advance the tail with wrap around
- Decrease count after each successful read
- After reading print the new value of the tail index on new line


Plan:
- In a for loop get the index of the element to return
    - using (tail+i) % capacity
    - check if the count < n then print Null
- print the final tail index

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

void read_bytes(CircularBuffer *cb, int n) {
    // Your logic here
    for(int i = 0; i < n; ++i)
    {
        if(cb->count > 0)
        {
            printf("%d", cb->buffer[cb->tail]);
            cb->tail = (cb->tail + 1) % cb->capacity;
            cb->count--;
        }
        else
        {
            printf("NULL");
        }
       
        if(i != n-1) printf(" ");
    }
    printf("\nTail: %d", cb->tail);
}

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;
}

Solving Approach