AoC2022 Day 3 C solution

#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#define MAX_LEN 64

char chars[] = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ";

int readLine(char* buffer, FILE* fp) {
    int result = fgets(buffer, MAX_LEN, fp);
    if (result == 0) return 0;
    buffer[strcspn(buffer, "\n")] = 0;
    return result;
}

char getSharedChar(char* line) {
    int i, j;
    int lineLength = strlen(line);
    for (i = 0; i < lineLength / 2; i++) {
        for (j = lineLength / 2; j < lineLength; j++) {
            if (line[i] == line[j]) {
                return line[i];
            }
        }
    }
    // It's hecked, lads
    return '';
}

char getBadge(char* lineA, char* lineB, char* lineC) {
    int i, j, k;
    int lineALength = strlen(lineA);
    int lineBLength = strlen(lineB);
    int lineCLength = strlen(lineC);
    for (i = 0; i < lineALength; i++) {
        for (j = 0; j < lineBLength; j++) {
            for (k = 0; k < lineCLength; k++) {
                if (lineA[i] == lineB[j] && lineB[j] == lineC[k]) {
                    return lineA[i];
                }
            }
        }
    }
    // It's hecked, lads
    return '';
}

int getScoreForChar(char c) {
    int i;
    int l = strlen(chars);
    for (i = 0; i < l; i++) {
        if (chars[i] == c) {
            return i+1;
        }
    }
    return -1;
}

void doStuff(FILE* fp) {
    char bufferA[MAX_LEN];
    char bufferB[MAX_LEN];
    char bufferC[MAX_LEN];
    char bufferASharedChar;
    char bufferBSharedChar;
    char bufferCSharedChar;
    char badge;
    int cursorAX = 14;
    int cursorAY = 5;
    int cursorBX = 14;
    int cursorBY = 11;

    int partOne = 0;
    int partTwo = 0;

    printf("Items:\n\n\n\n\n\nBadges:\n\n\nPart one:\nPart two:");

    while (readLine(bufferA, fp)) {
        readLine(bufferB, fp);
        readLine(bufferC, fp);

        bufferASharedChar = getSharedChar(bufferA);
        bufferBSharedChar = getSharedChar(bufferB);
        bufferCSharedChar = getSharedChar(bufferC);
        badge = getBadge(bufferA, bufferB, bufferC);

        partOne += getScoreForChar(bufferASharedChar);
        partOne += getScoreForChar(bufferBSharedChar);
        partOne += getScoreForChar(bufferCSharedChar);
        partTwo += getScoreForChar(badge);

        gotoxy(cursorAX, cursorAY);
        printf("%c%c%c", bufferASharedChar, bufferBSharedChar, bufferCSharedChar);
        cursorAX += 3;
        if (cursorAX > 74) {
            cursorAX = 14;
            cursorAY += 1;
        }

        gotoxy(cursorBX, cursorBY);
        printf("%c", badge);
        cursorBX += 1;
        if (cursorBX > 74) {
            cursorBX = 14;
            cursorBY += 1;
        }

        gotoxy(14, 14);
        printf("%d", partOne);
        gotoxy(14, 15);
        printf("%d", partTwo);
    }

    gotoxy(1, 16);
    printf("\n");
}

int main(int argc, char **argv) {
    FILE* fp;

    clrscr();
    printf("\n ADVENT OF CODE 2022 / DAY 03\n u/JohnGabrielUK\n\n");

    if (argc != 2) {
        printf("Usage: day3.exe [input file]\n");
    }

    fp = fopen(argv[1], "r");
    if (fp == NULL) {
        perror("Failed to open fail: ");
        return 1;
    }

    doStuff(fp);
    return 0;
}