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#include <stdio.h>
#include <stdlib.h>

struct Node
{
	struct Node *right;
	struct Node *left;
	int value;
};

void printTree(struct Node* n, int depth)
{
	int i;
	if(n==NULL) return;
	printTree(n->right, depth+1);
	for(i=0;i<depth;i++) printf("     ");
	printf("%5d\n",n->value);
	printTree(n->left, depth+1);
}

void replace(struct Node* n, int old, int new) {
	if(n==NULL) return;
	replace(n->right, old, new);
	if (n->value == old) n->value = new;
	replace(n->left, old, new);
}

int main(void)
{
//Baum erstellen
	struct Node* root = (struct Node*)malloc(sizeof(struct Node));
	root->value = 1;
	struct Node* left = (struct Node*)malloc(sizeof(struct Node));
	left->value = 2;
	struct Node* right = (struct Node*)malloc(sizeof(struct Node));
	right->value = 3;
	root->left = left;
	root->right = right;
	struct Node* leftleft = (struct Node*)malloc(sizeof(struct Node));
	leftleft->value = 4;
	left->left = leftleft;
//Ausgabe zur Kontrolle
	printTree(root, 0);
//Ersetzen des Inhalts
	replace(root, 2, 5);
	replace(root, 3, 7);
	printf("\n\n");
//erneute Ausgabe
	printTree(root, 0);
}