//PROG--TO SWAP 2 NIBBLS IN A BYTE BY MASKING//

/PROG--TO SWAP 2 NIBBLS IN A BYTE BY MASKING//

#include<stdio.h>

int main()

{

        int i=0,j=0;

        unsigned char set,byt[20]={0},num,ch,cp;

        ch=234;//I HAVE THIS NUMBER WHOSE TWO NIBBLES ARE TO BE EXCHANGED//

        num=cp=ch;

        ch=(ch & 0x0f);//MASK UPPER 4 BITS OF NUMBER BY 0..//

        ch=ch<<4;//MAKE LOWER 4 BITS TO UPPER 4 BY 4 RIGHT SHIFT...//

        cp=(cp & 0xf0);//MASK LOWER 4 BITS TO 0

        cp=cp>>4;//SHIFT UPPER 4 BITS TO LOWER 4 IN MAKING 4 RIGHT SHIFT //

        num=ch | cp;//MAKE OR CP TO CH//MEANS ORIGINALLY UPPER 4 BITS BECAME LOWER ONE& ORIGIONALLY LOWER 4 BITS BECAME UPPER ONE//NOW I GET NEED TO THIS REVERSED NIBBLE TO PRINT IN BINARY//

        while(num!=0)

        {

                //printf("num=%d\n",num);

                //byt[i]=byt[i]*10;//byt[i]=0 *10=0/////

                byt[i]=byt[i]|(num%2);//everytime when i found remainder....%2 ==0 or 1 ...that remainder is ored by byt[i]..... to make that number as byt[i]...//so everytime remainder is lefting in byt[] array..//

                printf("byt[%d]=%d\n",i,byt[i]);

                num=num/2;//SO DIVIDE NUMBER BY 2 EVERYTIME ...//

                i++;//INCREMENT i ...everytime ..in to put the ,value in byt ...means in binary number..//

        }

        for(j=(i-1);j>=0;j--)//represent that remainder array in reverse order to print proper binary order..//

                printf("%d",byt[j]);

      return 0;

}