Question

I am trying to write a method that determines if the square of the age of a person is equal to the current year. For example a man was aged 43 in 1849 and the square of 43 is 1849.
Below is my code for it but I dont know why my exception is not working because it is assumed that no body can live past 123 years

 public Boolean isAlive(int y){
     assert( y>=1888 && y<=2134);
     int age=0;
     while(age<=123){
         y=y+1;
         age=age+1;
         if(age*age==y){
             int c=age;
             return true;
             }
         }
      return false;
   }

Answer 1

The problem you are trying to solve appears to be

y + n = n^2

where y is the starting year and n is the age and both must be a positive whole number.

Rearranged this is

n = (sqrt(1 + 4 * y) + 1)/2;

e.g.

when y = 1806, n = 43, n + y = n * n = 1849.

when y = 1980, n = 45, n + y = 2025, n * n = 2025.

So you can write

public boolean squareAgeIfBorn(int year) {
   double n = (Math.sqrt(1 + 4 * year) + 1) / 2;
   return Math.abs(n - (long) n) < 1e-9; // i.e. if n is a whole number.
}