// Read a tree from a stream
// Example: //
// 10 black //
// / \ //
// 5 red 15 black //
// / \ / \ //
// null 7 black null null //
// / \ //
// null null //
// is represented as //
// 10 black
// 5 red
// null
// 7 black
// null
// null
// 15 black
// null
// null
// This is a recursive function
//
static bool readIntegerTree(RBTree& tree, FILE* f) {
tree.clear();
char line[256];
if (fgets(line, 254, f) == NULL)
return false;
line[254] = 0;
int len = strlen(line);
// Remove "\r\n" at the end of line
if (len > 0 && line[len-1] == '\n') --len;
if (len > 0 && line[len-1] == '\r') --len;
int i = 0;
while (i < len && isspace(line[i])) ++i;
if (i < len && (isdigit(line[i]) || line[i] == '-'))
{
int n = atoi(line + i);
bool red = false;
while (i < len && (isdigit(line[i]) || line[i] == '-')) ++i;
if (i >= len || !isspace(line[i])) return false;
while (i < len && isspace(line[i])) ++i;
if (i < len && line[i] == 'r') red = true;
RBTree leftSubtree;
if (!readIntegerTree(leftSubtree, f)) return false;
RBTree rightSubtree;
if (!readIntegerTree(rightSubtree, f)) return false;
RBTreeNode* rootNode = new RBTreeNode();
rootNode->red = red;
rootNode->value = new Integer(n);
tree.header.left = rootNode;
rootNode->parent = &(tree.header);
tree.numNodes = 1;
if (leftSubtree.size() > 0)
{
rootNode->left = leftSubtree.root();
leftSubtree.root()->parent = rootNode;
tree.numNodes += leftSubtree.size();
leftSubtree.header.left = 0;
leftSubtree.numNodes = 0;
}
if (rightSubtree.size() > 0)
{
rootNode->right = rightSubtree.root();
rightSubtree.root()->parent = rootNode;
tree.numNodes += rightSubtree.size();
rightSubtree.header.left = 0;
rightSubtree.numNodes = 0;
}
}
return true;
}
///== /////////////////////////////////////////////
int main() {
printf("Test of Red-Black Tree class\n");
printHelp();
FILE* f = NULL;
// Define a random tree with 20 nodes
time_t t = time(0); // Current time in seconds since 1 Jan 1970
srand(t);
RBTree tree;
char line[256];
while (true)
{
printf("Command>");
if (fgets(line, 254, stdin) == NULL) break;
// Parse a command
line[254] = 0;
int len = strlen(line);
// Remove "\r\n" at the end of line
if (len > 0 && line[len-1] == '\n') { line[len-1] = 0; --len; }
if (len > 0 && line[len-1] == '\r') { line[len-1] = 0; --len; }
int i = 0;
// Skip a space in beginning of line
while (i < len && isspace(line[i])) ++i;
int commandBeg = i;
while (i < len && isalpha(line[i])) ++i;
int commandEnd = i;
int commandLen = commandEnd - commandBeg;
if (strncmp("gentree", line+commandBeg, commandLen) == 0 || strncmp("gt", line+commandBeg, commandLen) == 0)
{
while (i < len && isspace(line[i])) ++i; // Skip a space
if (i >= len || !isdigit(line[i])) { printf("Incorrect command.\n"); printHelp(); continue; }
int n = atoi(line + i);
// Generate a random tree
tree.clear();
int j = 0; if (n > 100) n = 100; // Maximum 100 nodes
while (j < n)
{
Integer num(rand() % 100 + 1); RBTreeNode* node;
if (!tree.find(&num, tree.root(), &node)) { Integer* v = new Integer(num); tree.insert(node, v); ++j; }
}
// Print a tree to stdout
writeIntegerTree(tree.root(), stdout);
}
else if (strncmp("readtree", line+commandBeg, commandLen) == 0)
{
while (i < len && isspace(line[i])) ++i; // Skip a space
if ((f = fopen(line+i, "r")) == NULL) { perror("Could not open a file for reading"); continue; }
// Read a tree from a file
if (readIntegerTree(tree, f)) writeIntegerTree(tree.root(), stdout); else printf("Incorrect format.\n");
fclose(f); f = NULL;
}
else if (strncmp("writetree", line+commandBeg, commandLen) == 0)
{
while (i < len && isspace(line[i])) ++i; // Skip a space
if (i >= len) { printf("Incorrect command.\n"); printHelp(); continue; }
if ((f = fopen(line+i, "w")) == NULL) { perror("Could not open a file for writing"); continue; }
writeIntegerTree(tree.root(), f);
fclose(f); f = NULL;
}
///////////////////// ================================================
else if (strncmp("md", line+commandBeg, commandLen) == 0)
{
RBTreeNode*node = tree.root();
printf("Max depth = %d.\n", GetDepth(node));
printf("Black depth = %d.\n", GetBlackDepth(node));
}
///////////////////// ================================================
else if (strncmp("quit", line+commandBeg, commandLen) == 0) break; // end if
} // end while
return 0;
}
