lf-普通解法

解题思路:

注意事项:

参考代码:

    #include<stdio.h>

    #include<stdlib.h>

    #include<malloc.h>

    typedef struct tree{

        char data;

        struct tree *Lchlid,*Rchlid;

    }tree;

    tree *root;

    tree* build_tree(tree *root){

        char ch;

        scanf("%c",&ch);

        if (ch ==' ') {

            root=NULL;

        }

        else{

            root=(tree *)malloc(sizeof(tree));

            root->data=ch;

            root->Lchlid=build_tree(root->Lchlid);

            root->Rchlid=build_tree(root->Rchlid);

        }

        return root;

} 

    void preprint(tree *root){

        if(root==NULL)

            return;

        else{

            printf("%c ",root->data);

            preprint(root->Lchlid);

            preprint(root->Rchlid);

        }

}

    void inprint(tree *root){

        if(root==NULL) return;

        else{

            inprint(root->Lchlid);

            printf("%c ",root->data);

            inprint(root->Rchlid);

    }

}

    void postprint(tree *root){

        if(root==NULL)

            return;

        else{

            postprint(root->Lchlid);

            postprint(root->Rchlid);

            printf("%c ",root->data);

    }

}

    int main (){

        tree *root;

        root=build_tree(root);

        preprint(root);

        printf("\n");

        inprint(root);

        printf("\n");

        postprint(root);

        return 0;

}