What is accumulator?

Question

public class Prog2 {

public static void main(String[] args) {

int n = 10, t1 = 0, t2 = 1;
int total = 0;
System.out.print("First " + n + " terms: ");

for (int i = 1; i <= n; ++i)
{
System.out.print(t1 + " + ");

int sum = t1 + t2;
t1 = t2;
t2 = sum;
total= sum - 1;
}
System.out.println("Total: " +total);
}
}