PIC16F877A LCD Count UP and DOWN with range

/*--------------------------------------------------------/
    Name    : Mohd Syahri Fikri Bin Samusi

    LCD interfacing with PIC16F877A
    with RB interrupt. switch RB7 will count up
    and switch RB6 will count down. Range of
    counter from 250 to 300

    Date modified : 06 April 2012
/--------------------------------------------------------*/

#include <htc.h>
#include <pic16f877a.h>
#define _XTAL_FREQ 20000000
#include <lcd.c>

int k;
//----Interrupt Service function----
interrupt ISR(void) // Interrupt function definition
{
    if(RBIF) // if RB port change interrupt flag
    {
        RBIE = 0; // Disable RB port change interrupt

        if(!RB7)
        {
            k++; // Increment of the counter
            //__delay_ms(1000); //Delay for 1 second
        }

        if(!RB6)
        {
            k--; // Decrement of the counter
            //__delay_ms(1000); //Delay for 1 second
        }

        RBIF = 0; // Reset RB port change interrupt flag
        RBIE = 1; // Re-enable RB port change interrupt
    }
    GIE=1;
}

//----Main function----
void main( )
{
    char j[6];
    lcd_init( );
    TRISB = 0xF0;
    nRBPU = 0;
    lcd_putch ('\f');
    lcd_putc ("RB7 UP, RB6 DOWN ");

    RBIE = 1;   // Enable the RB port change interrupt
    GIE = 1;    // Global interrupt enable
    RBIF = 0;   // Clear RB port change interrupt flag
    PEIE = 1;   // Peripheral Interrupt Enable

    while (1)
    {
        if(k<250) k=250;
        if(k>300) k=300;

        // k++;//Increment the counter
        j[0]=k/10000+'0';
        j[1]=(k%10000)/1000+'0';
        j[2]=(k%1000)/100+'0';
        j[3]=(k%100)/10+'0';
        j[4]=k%10+'0';
        j[5]=0;
        lcd_gotoxy(2,0); //Go to the second line of LCD panel
        lcd_putc ("Now is ");
        lcd_putc (j);
        __delay_ms(1000); //Delay for 1 second
    }
}
//End of Program