아래 소스에서 도대체 무엇이 잘못된건지..도스창에 아무것도 나타나지 않습니다.
어디간 틀린건가요?

#include <stdio.h>

#define ESCAPE 27
#define OFFSET 32

struct sline {
    int row;
    int col;
    char *string;
};

static struct sline screen1[] = {
    {5, 5, "Do You Want To Know About"},
    {7, 10, "1. What This Program Does"},
    {9, 10, "2. How This Program Works"},
    {11, 10, "3. Exit This Program"},
    {13, 10, "Enter # AND RETURN"}
};
int size1 = sizeof(screen1) / sizeof(struct sline);

static struct sline screen2[] = {
    {5, 5, "It Demonstrates Menu Selections"},
    {7, 5, "Enter C To Go Back"},
};
int size2 = sizeof(screen2) / sizeof(struct sline);

static struct sline screen3[] = {
    {5, 5, "                        "},
    {5, 5, "Enter C To Go To Main Menu"},
};
int size3 = sizeof(screen3) / sizeof(struct sline);

static struct sline screen4[] = {
    {5, 5, "This Program Is Written In C"},
    {75, 5, "Enter C To Go To Main Menu"},
};
int size4 = sizeof(screen4) / sizeof(struct sline);

void main(void)
{
    int c;
    int d = 0;
    while (1){
        /*    메인화면 보여주기    */
        if (d == 0) dspscr(screen1, size1);
        cursor(20, 20);
        c = getchar();
        switch (c){
            case '1':
                dspscr(screen2, size2);
                keyin('C');
                d = 0;
                break;
            case '2':
                dspscr(screen3, size3);
                keyin('C');
                d = 0;
                break;
            case '3':
                exit(0);
                break;
            default:
                d = 1;
                break;
        }    /*    end: switch    */
    }    /*    end: while    */
}    /*    end: main    */

dspscr(screen, numline)
/*    화면 보여주기    */
struct sline screen[];    /* 줄의 배열    */
int numline;    /*    배열에 있는 숫자    */
{
    register int i;
    clrsc();
    for (i = 0; i < numline; i++){
        dspline(&screen[i]);
    }
return 0;
}

dspline(line)
/*    prints line on terminal screen    */
struct sline *line;    /* line to print    */
{
    cursor(line->row, line->col);
    strout(line->string);

    return 0;
}

cursor(row, col)
/* positions cursor at row.col
no check made on validity of row and col
this is terminal dependent    */
int row;
int col;
{
    putchar(ESCAPE);
    putchar('=');
    putchar(OFFSET + row);
    putchar(OFFSET + col);
    printf("\n\n");
    return;
}

strout(string)
/*    outputs a string to terminal,
not including null char */
/*    no check is made for error on outputs    */
char *string;    /*    string to outputs    */
{
    while (*string){
        putchar(*string++);
    }
return 0;
}

clrsc()
/*    clears the screen    */
/*    this is terminal dependent    */
{
    putchar(ESCAPE);
    putchar('V');
    putchar(ESCAPE);
    putchar('T');
    putchar(ESCAPE);
    putchar('O');
    putchar('@');
    putchar(ESCAPE);
    putchar('9');
    putchar('P');
    return 0;
}

keyin(chr)
/*    waits till chr is pressed    */
int chr;    /*    character to wait for    */
{
    while (1){
        cursor(20, 20);
        if (chr == toupper(getchar())) break;
    }
return chr;
}