LCD shift right and shift left bugs

I have made a library for LCD with HD44780 controller in it, and from the datasheet I read that the code 0x18 will shift the entire display one position to the left, but when I made that, the display disappears. I have also read that 0x1C shifts the entire display one position to the right but when I made it, the entire display shifts to left.

My code:

    /*
 * main.c
 *
 * Created: 11/14/2013 7:54:02 PM
 *  Author: A R M T
 */ 
#include <avr/io.h>

#define F_CPU 1000000UL
#define __DELAY_BACKWARD_COMPATIBLE__
#include <util/delay.h>
#define LCD_DPRT PORTA                   //LCD DATA PORT
#define LCD_DDDR DDRA                    //LCD DATA DDR
#define LCD_DPIN PINA                    //LCD DATA PIN
#define LCD_CPRT PORTB                   //LCD COMMANDS PORT
#define LCD_CDDR DDRB                    //LCD COMMANDS DDR
#define LCD_CPIN PINB                    //LCD COMMANDS PIN
#define LCD_RS 0                         //LCD RS
#define LCD_RW 1                         //LCD RW
#define LCD_EN 2                         //LCD EN

//*************************************************************

void delay_us(unsigned int d);
void lcdCommand(unsigned char cmnd);
void lcdData(unsigned char data);
void lcd_init(void);
void lcd_gotoxy(unsigned char x, unsigned char y);
void lcd_print(char *str);


//*************************************************************
void delay_us(unsigned int d)
{
    _delay_us(d);
}
//*************************************************************
void lcdCommand(unsigned char cmnd)
{
    LCD_DPRT = cmnd;                   //send cmnd to data port
    LCD_CPRT &= ~(1<<LCD_RS);          //RS = 0 for command
    LCD_CPRT &= ~(1<<LCD_RW);          //RW = 0 for write
    LCD_CPRT |= (1<<LCD_EN);           //EN = 1 for H-to-l pulse
    delay_us(1);                       //Wait to make enable wide
    LCD_CPRT &= ~(1<<LCD_EN);          //EN = 1 for H-to-l pulse
    delay_us(100);                     //Wait to make enable wide
}
//*************************************************************
void lcdData(unsigned char data)
{
    LCD_DPRT = data;                    //send data to data port
    LCD_CPRT |= (1<<LCD_RS);            //RS = 1 for data
    LCD_CPRT &= ~(1<<LCD_RW);           //RW = 0 for write
    LCD_CPRT |= (1<<LCD_EN);            //EN = 1 for H-to-L pulse
    delay_us(1);                        //wait to make enable wide
    LCD_CPRT &= ~(1<<LCD_EN);           //EN = 0 for H-to-L pulse
    delay_us(100);                      //wait to make enable wide
}
//*************************************************************
void lcd_init(void)
{
    LCD_DDDR = 0xFF;
    LCD_CDDR = 0xFF;

    LCD_CPRT &= ~(1<<LCD_EN);           //LCD_EN = 0
    delay_us(15000);                    //wait for init
    lcdCommand(0x38);                   //init. LCD 2 line, 5 * 7 matrix
    lcdCommand(0x0E);                   //display on, cursor on
    lcdCommand(0x01);                   //clear LCD
    delay_us(2000);                     //wait
    lcdCommand(0x06);                   //shift cursor right
}
//*************************************************************
void lcd_gotoxy(unsigned char x, unsigned char y)
{
    unsigned char firstCharAdr[] = {0x80, 0xC0, 0x94, 0xD4};
    lcdCommand(firstCharAdr[y-1] + x - 1);
    delay_us(100);
}
//*************************************************************
void lcd_print(char *str)
{
    unsigned char i = 0;
    while (str[i] != 0)
    {
        lcdData(str[i]);
        i++;
    }
}
//*************************************************************

int main(void)
{

    lcd_init();
    lcd_gotoxy(1,1);
    lcd_print("Armia");
    lcd_gotoxy(1,2);
    lcd_print("Wagdy");
    _delay_ms(1000 / 2);
    lcdCommand(0x18);   // Shift the entire display one position to the left
    while(1);
    return 0;
}

I meant that when I burned this code I excepected that aftr(1000 / 2) ms this output will shift to left

but what appears was(the word disappears instead of shifting left one postition)

Can any one help me in that problem please?!

I tried your code in proteus version 7.10 and shift left works fine

Note that you are using the _delay_us function with a variable parameter, that is not the correct way, it gives wrong delays and generates big hex file because it forces the float library to be included

delay.h manual

Note: In order for these functions to work as intended, compiler optimizations must be enabled, and the delay time must be an expression that is a known constant at compile-time. If these requirements are not met, the resulting delay will be much longer (and basically unpredictable), and applications that otherwise do not use floating-point calculations will experience severe code bloat by the floating-point library routines linked into the application.

Replace the code with a loop that calls the delay several times

while (d--) 
{
  _delay_ms(1);
}