Swap bits in a number in C [duplicate]

Answer 1

#include 
#include 
#include 
void main() { 
    int q,t,n,a[20],j,temp;
    int i=0;
    int s=0;
    int tp=0;
    clrscr();
    printf("\nenter the num\n");
    scanf("%d",&n);
    t=n;
    while(n>0) {
        a[i]=n%2;
        i++;
        n=n/2;
    }
    printf("\n\n");
    printf("num:%d\n",t);
    printf("number in binary format:");
    for(j=i-1;j>=0;j--) {
        printf("%d",a[j]);
    }
    printf("\n");
    temp=a[i-1];
    a[i-1]=a[0];
    a[0]=temp;
    printf("number in binary format wid reversed boundary bits:");
    for(j=i-1;j>=0;j--) {
        printf("%d",a[j]);
    }
    printf("\n");
    q=i-1;
    while(q>=0) {
        tp=pow(2,q);
        s=s+(tp*a[q]);
        q--;
    }
    printf("resulatnt number after reversing boundary bits:%d",s);
    printf("\n");
    getch();
}