Question

without running on java, what is the final answer, please show your work.

public class sample {
public static void main(String[] args){
Sample x = new Sample();
int i = 10;
int b = x.g(i);
System.out.println(b + i);
}
public int f(int d){
int n = 0;
while(n*n < d){
n++;
}
return n-1;
}
public int g(int a){
int b = 0;
int c;
for(int n = 0; n < a; n++){
c = f(n);
b = b + c;
}
return b;
}
}

Answer 1

Recording all values of the variables in each method as we go:
-main:
i = 10
b = x.g(10) = 12 (returned from g)
---
after method g
i = 10
b = 12*

-f:
d = 0(passed from g's c variable)
n = 0
-while loop-
1st pass:
false, as 0*0 is not <0
n = n - 1 = 0 - 1 = -1
.
.
.
Keep comparing until n^2 is less than d passed in

-g:
a = 10 (passed from main's b variable)
b = 0;
c = NULL;
-for loop-
...n = 0
...c = f(0) = -1 (returned from f's return statement, 1st pass)
...b = b + c = 0 + -1 = -1
(And now after the first pass our variables are:
a = 10
b = -1
c = -1)

This continues until n=9 for n !>= 10
...b = 12
return b; // b is 12, and now we return to main
----------------------------------------------------------------------------------------
b + i = 12 + 10 = 22**
We are really only needing to find what b is, since i does not change in main. It's a lot of back and forth between method g and method f for b but we got it!

This seems like a lot but it's mostly pattern recognition bc of all the loops. It really helps to write down variables and update their values as you go thru code, just a tip.
Also, if you can, paste this into java and add print statements like: "b before adding" and "b after adding", etc. to see how, where, and why these variables change.

Answer 2

thanks @.