#include <bits/stdc++.h> using namespace std; typedef string ElemType; typedef struct BitNode { ElemType data; struct BitNode *lchild,*rchild; } BitNode,*BiTree; //char sc[10]= {"+-*/"}; void CreateBiTree(BiTree &t) { string ch; cin >> ch; if(ch[0] == '#') t = NULL; else { t = new BitNode; t->data = ch; CreateBiTree(t->lchild); CreateBiTree(t->rchild); } } void InOrderTraverse(BiTree t) { if(t) { string op = t->data; if(op[0]<'0' || op[0]>'9') cout << '('; InOrderTraverse(t->lchild); cout << t->data ; InOrderTraverse(t->rchild); if(op[0]<'0' || op[0]>'9') cout << ')'; } /***********************************/ } int main() { BiTree tree = new BitNode; string ch; while(cin >> ch) { tree->data = ch; CreateBiTree(tree->lchild); CreateBiTree(tree->rchild); InOrderTraverse(tree); printf("\n"); } return 0; }用c语言实现

这段代码是C++语言实现的，不是C语言。如果想要在C语言中实现，可以参考下面的代码：

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

typedef char ElemType;
typedef struct BitNode {
    ElemType data;
    struct BitNode *lchild, *rchild;
} BitNode, *BiTree;

void CreateBiTree(BiTree *t)
{
    char ch;
    scanf("%c", &ch);
    if (ch == '#') {
        *t = NULL;
    } else {
        *t = (BitNode *)malloc(sizeof(BitNode));
        (*t)->data = ch;
        CreateBiTree(&((*t)->lchild));
        CreateBiTree(&((*t)->rchild));
    }
}

void InOrderTraverse(BiTree t)
{
    if (t) {
        char op = t->data;
        if (op < '0' || op > '9')
            printf("(");
        InOrderTraverse(t->lchild);
        printf("%c", t->data);
        InOrderTraverse(t->rchild);
        if (op < '0' || op > '9')
            printf(")");
    }
}

int main()
{
    BiTree tree;
    while (scanf("%c", &(tree->data)) != EOF) {
        CreateBiTree(&(tree->lchild));
        CreateBiTree(&(tree->rchild));
        InOrderTraverse(tree);
        printf("\n");
    }
    return 0;
}