Print an int in C without Printf or any functions

Question

I have an assignment where I need to print an integer in C without using printf, putchar, etc. No header files allowed to be included. No function calls except for anything

Answer 1

You can convert an int to char * , char * and display this char* :

char        *put_int(int nb)
{
 char       *str;

 str = malloc(sizeof(char) * 4);
 if (str == NULL)
   return (0);
 str[0] = (nb / 100) + '0';
 str[1] = ((nb - ((nb / 100 * 100 )) / 10) + '0');
 str[2] = ((nb % 10) + '0');
 return (str);
}

void        put_str(char *str)
{
 while (*str)
   write(1, str++,1);
}

int main(void)
{
 put_str(put_int(42));
 return (0);
}