update btree demo & comments

Author: fuli

include/btree.h

@@ -22,7 +22,7 @@
 #define __BTREE_H__
 
 #include <stdio.h>
-#include <iostream>
+#include <assert.h>
 #include <stdint.h>
 #include <stdlib.h>
 #include <string.h>
@@ -121,12 +121,6 @@ namespace alg {
 if (i<x->n && k == x->key[i]) {// search in [0,n-1]
 ret.offset = x->offset;
 ret.idx = i;
-/*
- int t;
- for (t=0;t<x->n;t++) {
- printf("%d ",x->key[t]);
- }
- */
 return ret;
 } else if (x->flag & LEAF) {// leaf, no more childs
 ret.offset = 0;
@@ -246,10 +240,10 @@ namespace alg {
 
 if (i >= 0 && x->key[i] == k) {// key exists in this node.
 if (x->flag & LEAF) {
-printf("in case 1 [%d] [%d]\n", i,x->n);
+//printf("in case 1 [%d] [%d]\n", i,x->n);
 case1(x, i, k);
 } else {
-printf("in case 2 [%d] [%d]\n", i,x->n);
+//printf("in case 2 [%d] [%d]\n", i,x->n);
 case2(x, i, k);
 }
 } else {
@@ -278,9 +272,8 @@ namespace alg {
 std::auto_ptr<node_t> y(READ(x, i));
 if (y->n >= T) {
 int32_t k0 = y->key[y->n-1];
-printf("case2a %d %d\n", k0, x->key[i]);
+//printf("case2a %d %d\n", k0, x->key[i]);
 x->key[i] = k0;
-printf("key[i] %d\n", k0, x->key[i]);
 WRITE(x);
 delete_op(y.get(), k0);
 return;
@@ -295,7 +288,7 @@ namespace alg {
 std::auto_ptr<node_t> z(READ(x, i+1));
 if (z->n >= T) {
 int32_t k0 = z->key[0];
-printf("case2b %d %d\n", k0, x->key[i]);
+//printf("case2b %d %d\n", k0, x->key[i]);
 x->key[i] = k0;
 WRITE(x);
 delete_op(z.get(), k0);
@@ -308,7 +301,7 @@ namespace alg {
 // pointer to z, and y now contains 2t - 1 keys. 
 // Then free z and recursively delete k from y.
 if (y->n == T-1 && z->n == T-1) {
-printf("case2c");
+//printf("case2c");
 // merge k & z into y
 y->key[y->n] = k;
 
@@ -340,7 +333,9 @@ namespace alg {
 delete_op(y.get(), k);
 return;
 }
-printf("other in case2");
+
+// cannot reach here
+assert(false);
 }
 
 void case3(node x, int32_t i, int32_t k) {
@@ -354,7 +349,7 @@ namespace alg {
 if (ci->n == T-1) {
 std::auto_ptr<node_t> left(READ(x, i-1));
 if (i-1>=0 && left->n >= T) {
-printf("case3a, left");
+// printf("case3a, left");
 // right shift keys and childs of x.c[i] to make place for a key
 // right shift ci childs
 int j;
@@ -381,7 +376,7 @@ namespace alg {
 // case 3a. right sibling
 std::auto_ptr<node_t> right(READ(x, i+1));
 if (i+1<=x->n && right->n >= T) {
-printf("case3a, right");
+// printf("case3a, right");
 ci->key[ci->n] = x->key[i];// append key from x
 ci->c[ci->n+1] = right->c[0];// append child from right
 ci->n = ci->n+1;
@@ -409,9 +404,7 @@ namespace alg {
 // with one sibling, which involves moving a key from x down into the new
 // merged node to become the median key for that node.
 if ((i-1<0 ||left->n == T-1) && (i+1 <=x->n || right->n == T-1)) {
-std::cerr << "case3b in";
 if (left->n == T-1) {
-std::cerr<<"case3b, left";
 // copy x[i] to left
 left->key[left->n] = x->key[i];
 left->n = left->n + 1;
@@ -452,7 +445,6 @@ namespace alg {
 delete_op(left.get(), k);
 return;
 } else if (right->n == T-1) {
-std::cerr<<"case3b, right";
 // copy x[i] to x.c[i]
 ci->key[ci->n] = x->key[i];
 ci->n = ci->n + 1;

src/btree_demo.cpp

@@ -8,11 +8,14 @@ int main(void) {
 
 for (i=0;i<1000;i++) {
 x.Insert(i);
+printf("insert %d\n", i);
 }
 
 for (i=0;i<1000;i++) {
 x.DeleteKey(i);
 BTree::nr r = x.Search(i);
-printf("key[%d] offset[%x] idx[%d]\n", i, r.offset, r.idx);
+if (r.idx == -1) {
+printf("key[%d] removed\n", i);
+}
 }
 }