1. Should these measures fail to restore order, harsher restrictions will have to be imposed.

Are “should” and “if” interchangeable at the beginning of a sentence? (**Should** he study hard, no doubt he would pass this course OR If he study hard, no doubt he would pass this course.)

If Not then in what cases we can interchange them. 

2. If he should study hard........OR Should he study hard.......

Is this sentence conditional?