$6.$ Given an array of $2$n elements a$1,$a$2,...$an$,$b$1,$b$2,.....,$bn$.$ We want to shuffle the array to get a$1,$b$1,$a$2,$b$2,....$an$,$bn without using any new array. Give an algorithm to solve the problem.

Use your algorithm to write a program to shuffle array

int a$[10]=\{1,3,5,7,9,2,4,6,8,10\}$ ; should become a$[10]=\{1,2,3,4,5,6,7,8,9,10\}$;