Lecture 25

Recursion

• Stack
• space for parameters / local values/ return values
• indirect recursion
• a method which calls iteself with different parameters
• recursion
• a method which calls itself within itself
• if this is done wrong you get a stack overflow error

int fact(int n)
{
//base case

if (n == 1) { return n}
return n * fact(n-1);
}

• famous recursive methods
• binary search
• mergesort
• quick sort
• towers of hanoi

int bSearch(int[]A, int key, int l, int r)

{
// base case

if (l>r) return -(l + 1)
int m = (l + r) / 2;
if (A[m] == key ) return m;
if (A[m] < face="courier new">return bSearch( A, key, m+1, r)
return bSearch(A, key, L, m-1);

}


these were the notes i got when turnpin was in class, he doesn't write on the board too often so i hope this helps.