main()                                                       
   {                                                            
       int  number;                                             
                                                                
       printf("Enter an integer number\n");                     
       scanf ("%d", &number);                                   
                                                                
       if ( number < 100 )                                      
         printf("Your number is smaller than 100\n\n");        
       else                                                     
         printf("Your number contains more than two digits\n");
   }   
                                                         

Output                                                       
                                                                
   Enter an integer number                                      
   54                                                           
   Your number is smaller than 100                              
   Enter an integer number                                      
   108                                                          
   Your number contains more than two digits