Searching other element in struct in Binary Search Tree in

Searching other element in struct in Binary Search Tree in
i have already implemented whole code...the BST is sorted by ID.But what can i do to find the highest number of other element?
struct TNode {
int id;
char name[100];
float balance;
TNode * left;
TNode * right;
};
bool addCustomer (TNode ** root,char * name,int id,float bal){
if (*root == NULL){
TNode * newNode = (TNode*)malloc(sizeof (TNode));
if (newNode == NULL)
return false;
newNode->id = id;
strcpy (newNode->name,name);
newNode->balance=bal;
newNode->left = NULL;
newNode->right = NULL;
*root = newNode;
}else if ((*root)->id < id){
addCustomer (&((*root)->right),name,id,bal);
}else if ((*root)->id > id){
addCustomer (&((*root)->left),name,id,bal);
}
return true;
}
//add customer function sort the BST with ID
TNode * findCustomer(TNode * root,int id){
if (root == NULL){
return NULL;
}else{
if (root->id < id){
return (findCustomer (root->right,id));
}else{
if (root->id > id){
return (findCustomer (root->left,id));
}else{
return root;
}
}
}
}
TNode * findRichestCustomer(TNode * root){
//i want to find the node that have highest amount...what should i put in here?
}
these are my codes.i am just beginner in C language...
i don't know what should i write inside the findRichestCustomer function with just one parameter passed.
need help...

Yes. All fingerprints are different. The law enforcement agencies use fingerprints to identify the real criminals. The fingerprints are also used in checking the identities of visitors, tourists, and employees.