C语言 求一个二叉树中位于先序序列中第k个位置的结点的值

编制一个递归算法，求一个二叉树中位于先序序列中第k个位置的结点的值#includestdio.h#includestdlib.h#defineNULL0typedefcharTElemType;typedefstructBiNode{structBiNode*lchild;TElemTypedata;structBiNode*rchild;}BiNode;structBiNode*CreateBiTree(structBiNode*T){TElemTypea;structBiNode*t;scanf(%c,&a);if(a=='')T=NULL;else{t=(structBiNode*)malloc(sizeof(BiNode));if(t!=NULL){t-data=a;T=t;T-lchild=CreateBiTree(T-lchild);T-rchild=CreateBiTree(T-rchild);}}returnT;}voidshow(structBiNode*T){if(T!=NULL){printf(%c,T-data);show(T-lchild);show(T-rchild);}}inttree(structBiNode*T,intk,inta){if(T==NULL){a=a-1;returna;}else{if(a==k){printf(%c,T-data);}else{a=tree(T-lchild,k,a+1);a=tree(T-rchild,k,a+1);}returna;}}voidmain(){inti,k;structBiNodet;structBiNode*T;T=&t;printf(inputelementsofBiTree:);T=CreateBiTree(T);printf(\ntheBiTreeis:);show(T);printf(\ninputk:);scanf(%d,&k);printf(\ntheresultis:);tree(T,k,1);}