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

char *readFile(char *fileName) {
    FILE *file = fopen(fileName, "r");
    char *code;
    size_t n = 0;
    int c;

    if (file == NULL) return NULL;
    fseek(file, 0, SEEK_END);
    long f_size = ftell(file);
    fseek(file, 0, SEEK_SET);
    code = malloc(f_size);

    while ((c = fgetc(file)) != EOF) {
        code[n++] = (char)c;
    }

    code[n] = '\0';

    return code;
}

int main()
{
    FILE *output = fopen("c.txt", "w");

    if(!output)
        exit(1);

    char *input = readFile("a.txt");
    char *input_b = readFile("b.txt");

    if(!input)
        exit(2);

    if(!input_b)
        exit(3);

    for(int i = 0; i < strlen(input); i++)
    {
        char in = input[i];
        if(in == '<' || in == '>' || in == '=')
        {
            fputc(in, output);
            fputc(' ', output);
        }
    }

    for(int i = 0; i < strlen(input_b); i++)
    {
        char in = input_b[i];
        if(islower(in))
        {
            fputc(in, output);
            fputc(' ', output);
        }
    }

    fclose(output);

    printf("Done!\n");
    return 0;
}