Fuck strings in C

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

typedef unsigned int uint;

typedef unsigned char bool;
#define true 1
#define false 0

#define write(buf, str, pos, affect_pos) { \
    uint l = strlen(str); \
    for(uint i=0;i<l;i++) { \
        buf[pos+i]=str[i]; \
    } \
    if(affect_pos) { \
        pos += l; \
    }}
char* join_args(char* strings[], char* seperator, int count) {
    char* str = NULL;
    size_t total_length = 0;
    int i = 0;
    for (i = 0; i < count; i++) total_length += strlen(strings[i]);
    total_length++;
    total_length += strlen(seperator) * (count - 1);
    str = (char*) malloc(total_length);
    str[0] = '\0';
    for (i = 1; i < count; i++) {
        strcat(str, strings[i]);
        if (i < (count - 1)) strcat(str, seperator);
    }
    return str;
}
int main(int arg_count, char* args[]) {
    uint buf_size = 2;
    char* arg_s = join_args(args,"",arg_count);
    uint len = strlen(arg_s);
    for(uint i=0;i<len;i++) {
        char c = arg_s[i];
        if(!isdigit(c)) {
            fputs("Usage: kek (numbers)\n", stderr);
            return 1;
        }
        if(c=='1') {
            buf_size+=2;
        } else if(c=='3'||c=='7') {
            buf_size+=3;
        } else {
            buf_size+=4;
        }
    }
    uint pos=0;
    char line_one[buf_size];
    char line_two[buf_size];
    char line_thr[buf_size];
    for(uint i=0;i<buf_size;i++) {
        line_one[i]=' ';
        line_two[i]=' ';
        line_thr[i]=' ';
    }
    for(uint i=0;i<len;i++) {
        char c = arg_s[i];
        if(c=='0') {
            write(line_one, " _  ", pos, false);
            write(line_two, "| | ", pos, false);
            write(line_thr, "|_| ", pos, true);
        } else if(c=='1') {
            write(line_one, "  ", pos, false);
            write(line_two, "| ", pos, false);
            write(line_thr, "| ", pos, true);
        } else if(c=='2') {
            write(line_one, " _  ", pos, false);
            write(line_two, " _| ", pos, false);
            write(line_thr, "|_  ", pos, true);
        } else if(c=='3') {
            write(line_one, "_  ", pos, false);
            write(line_two, "_| ", pos, false);
            write(line_thr, "_| ", pos, true);
        } else if(c=='4') {
            write(line_one, "    ", pos, false);
            write(line_two, "|_| ", pos, false);
            write(line_thr, "  | ", pos, true);
        } else if(c=='5') {
            write(line_one, " _  ", pos, false);
            write(line_two, "|_  ", pos, false);
            write(line_thr, " _| ", pos, true);
        } else if(c=='6') {
            write(line_one, " _  ", pos, false);
            write(line_two, "|_  ", pos, false);
            write(line_thr, "|_| ", pos, true);
        } else if(c=='7') {
            write(line_one, "_  ", pos, false);
            write(line_two, " | ", pos, false);
            write(line_thr, " | ", pos, true);
        } else if(c=='8') {
            write(line_one, " _  ", pos, false);
            write(line_two, "|_| ", pos, false);
            write(line_thr, "|_| ", pos, true);
        } else if(c=='9') {
            write(line_one, " _  ", pos, false);
            write(line_two, "|_| ", pos, false);
            write(line_thr, " _| ", pos, true);
        }
    }
    line_one[buf_size-1] = 0;
    line_two[buf_size-1] = 0;
    line_thr[buf_size-1] = 0;
    puts(line_one);
    puts(line_two);
    puts(line_thr);
}
/*
 Anonymous  ⋯  EzMake  Projects  kek  bin/kek 42069
     _   _   _   _
|_|  _| | | |_  |_|
  | |_  |_| |_|  _|
 Anonymous  ⋯  EzMake  Projects  kek 
*/