16 . uppercase and lowercase convert .

 

A -> 01000001          a -> 01100001

B -> 01000010          b -> 01100010

C -> 01000011          c -> 01100011

  .                      .

Z -> 01011010          z -> 01111010

 

Observations : fifth bit from the right is set from lowercase serial .

Mask = 1<<5  = 00100000

Ch  = Ch | Mask            : uppercase -> lowercase

Ch  = Ch &( ~Mask )     : lowercase -> uppercase

Code :

int t,n,i;     cin>>t;     while(t--)     {         char ch;         cin>>ch;         int mask = 1<<5;         ch = ch | mask; //uppercase - lowercase         cout<<ch<<' ';         mask = ~(mask);         ch = ch & mask;         cout<<ch<<endl;     }