if there is constraint a[i]<=10^5…it means my input int a[i] should not greater than 10^5. But what if any of my input is greater than 10^5 should it come out of the loop…or should continue the program for left entries??

Constraint means that in the given input, which your program is reading, a[i] is \le {10}^{5}. It is a way of problem setter saying that, in the test cases which will evaluate your program, a[i] is \le {10}^{5}