C Program for setting of bits in one byte from 7 to 4 bits with 5 without changing remaing values

Question

Say you are given "Hello World"
Output should be "olleH dlroW"

Answer 1

Say your input is integer a (4 bytes) and you want set the bits from 4 to 7 then you need to do bitwise OR with a number which has 1 at those bits and 0 as remaining bits;

a = a | 0x00000074 
// 0x74 is 01111000 in binary.

Answer 2

//C Program for setting of bits in one byte from 7 to 4 bits with 5 without changing remaing values
num=num|1<<4;
num=num&~(1<<5);
num=num|1<<6;
num=num&~(1<<7);
printf("%d",num);