c - 将 char 从字符串传递到函数

Question

我正在尝试将一些文本翻译为莫尔斯字母。当我发送一个字母来运行时，它可以正常工作，但我想让它写一个单词，所以我尝试用指针索引一个一个地发送单词，但它不会发生，请帮忙。

<小时/>

树结构:

typedef struct tree
{
    char *letter;
    char *morscode;
    struct tree *left;
    struct tree *right;
} tree;

<小时/>

功能:

tree *root=NULL;

void add (char* letter, char* morscode) {
    if (root == NULL) {
        root = (tree *)malloc(sizeof(tree));
        root->letter   = letter;
        root->morscode = morscode;
        root->left     = NULL;
        root->right    = NULL;
    }
    else
    {
        tree *new = (tree *)malloc(sizeof(tree));
        new->letter   = letter;
        new->morscode = morscode;
        new->left     = NULL;
        new->right    = NULL;

        tree *node = root, 
             *mom;
        while (node != NULL) {
            mom = node;
            if (strcmp(letter, dugum->letter) == -1)
                node = node->left;
            else 
                node = node->right;
        }
        if (strcmp(letter, mom->letter) == -1) 
            mom->right = new;
        else 
            mom->right = new; 
    }
}

tree *searchbyletter(char& letter, agac *node) {

    if(strcmp(letter,node->letter) == -1)
        searchbyletter(letter, node->left);
    else if(strcmp(letter, node->letter) == 1)
        searchbyletter(letter, node->right);
    else
        return node;
}

void write(char *letter) {
    int x = strlen(letter),
        i;
    for(i = 0; i < x; i++) {
        printf("%s", searchbyletter(letter[i], root)->morscode);    
    }
}

void preorder(tree *node) {
    if (node != NULL) {
        printf(" %s ", node->letter);
        preorder(node->left);
        preorder(node->right);
    }
}

void inorder(tree *node) {
    if (node != NULL) {
        inorder(node->left);
        printf(" %s ", node->letter);
        inorder(node->right);
    }
}

void postorder(tree *node) {
    if (node!=NULL) {
        postorder(node->left);
        postorder(node->right);
        printf(" %s ", node->letter);
    }
}

<小时/>

主要: [我手动初始化了摩尔斯电码和字母。]

void main() {
    char* arr[27][2] = {
        {" ", " "}, {"E", "."}, 
        {"T", "-"}, {"I", ".."}, 
        {"A", ".-"}, {"N", "-."},
        {"M", "--"}, {"S", "..."}, 
        {"U", "..-"}, {"R", ".-."}, 
        {"W", ".--"}, {"D", "-.."},
        {"K", "-.-"}, {"G", "--."}, 
        {"O", "---"}, {"H", "...."}, 
        {"V", "...-"}, {"F", "..-."},
        {"L", ".-.."}, {"P", ".--."}, 
        {"J", ".---"}, {"B", "-..."}, 
        {"X", "-..-"}, {"C", "-.-."},
        {"Y", "-.--"}, {"Z", "--.."}, 
        {"Q", "--.-"}
    };
    int i, j;
    for(i = 0; i < 27; i++) {
        add(arr[i][0], arr[i][1]);  
    }
    preorder(kok);
    printf("\n");
    inorder(kok);
    printf("\n");
    postorder(kok);
    printf("\n");
    write("HELLO WORLD");
}

Answer 1

我的猜测是问题出在使用 strcmp 函数比较单个字符(例如，strcmp(letter,node->letter))。

此函数 (strcmp) 比较以 null 结尾的 C 字符串，因此在您的情况下，当您尝试比较字母“B”时，它实际上会比较字符串“BA”。

您可以使用 == 运算符比较字符，如下所示:
if(字母==节点->字母)


但是，当然，如果没有完整的代码片段，就很难说。