In C++, it is faster to process a sorted array than an unsorted array because of branch prediction. In computer architecture, a branch prediction determines whether a conditional branch (jump) in the instruction flow of a program is likely to be taken or not.
if(arr[i] > 50) { Do some operation B } else { Do some operation A }
If we run this code for 100 elements in unsorted and sorted order below things will be happened:
1,2,3,4,5,……50,51………100 A,A,A,A,A A,B B It will load the correct branch in pipeline and correct sequence A,A,A, A,A,A,A,A A,B B
5,51,6,90,4,49,60… A,B,A,B,A,A,A,B
Branch prediction doesn’t play its significant role here. It is very difficult to predict the right operation between A and B.