Can someone explain? C#

Question

I met this code by doing challenges, can someone explain how is this possible that b = 5?

int a = 0; int b = 0;
while(a<3) {
++a;
a*=a;
b+=a;
}
Console.Write(b);
//output: 5

Answer 1

1st iteration:
0<3
++a, a=1
a*=a, a=1
b+=a, b=1

2nd iteration:
1<3
++a, a=2
a*=a, a=4
b+=a, b=1+4, b=5

3rd iteration:
4<3 false, end of while loop

Console.Write(b) , output is 5

Answer 2

maksonios The loop round 2 times..
1 time,
Outside loop a = 0
Inside loop ++a//(a=1)
a*=a//(a=1)
b+=a//(b=0+1=1)
2 time,
Outside loop a = 1
Inside loop ++a//(a=2)
a*=a//(a=4)
b+=a//(b=4+1=5)
//loop finish.
Output b= 5

Answer 3

Thanks a lot guys, now I understand how while and for works