Chess.c

#include <stdio.h>
#include <stdbool.h>

struct chess {
    int row;
    char column;
};

bool isValid(struct chess position) {
    return position.column >= 'a' && position.column <= 'h' && position.row >=1 && position.row <= 8;
}

bool knight(struct chess from, struct chess to) {
    if (!isValid(from) || !isValid(to)) {
        return false;
    }

    int rowMove = from.row - to.row;
    int colMove = from.column - to.column;

    if (rowMove == 1 || rowMove == -1) {
        return colMove == 2 || colMove == -2;
    } else if (rowMove == 2 || rowMove == -2) {
        return colMove == 1 || colMove == -1;
    }

    return false;
}