如何集成前缀检查器以根据文件读取找到完整的单词

Question

问题：I可以搜索文件并根据用户输入的数字打印单词(文本-消息号转换)，“购买”我还应该能够根据输入的数字的一部分找到完整的单词，因此. 72将返回pa、ra、sa和sc.它会在我的文件中找到单词，如party、radio、sandwich和scanner。

我尝试过使用前缀函数，但是我无法正确地集成它们。startsWith函数就是一个例子。

这些单词基于一个编号的键盘，如：字母电话键盘

代码：

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


const char numbered_letters[10][5] = {"", "", "abc", "def", "ghi", "jkl",
                                      "mno", "pqrs", "tuv", "wxyz"};



bool startsWith(const char *pre, const char *str) {
    size_t lenpre = strlen(pre),
            lenstr = strlen(str);
    return lenstr < lenpre ? false : strncmp(pre, str, lenpre) == 0;
}

void isEqual(char input[]) {
    int i = 0;
    //input[strlen(input)] = 0;
    startsWith(input, input);
    printf("check:  %s\n", input);
    //creating file
    FILE *fp = fopen("words_alpha.txt", "r");
    char str[32]; /* Handles largest possible string in the list which is: dichlorodiphenyltrichloroethane*/
    //fseek(fp, 0, SEEK_SET);
    if (fp == NULL) {
        printf("Error! No file!\n");
    } else {
        //printf("Enter a number to be converted into a word-list");
        //scanf("%s", str);

        while (!feof(fp)) {
            fscanf(fp, "%s", str);
            i = strncmp(input, str, 32);
            if (i == 0) {
                printf("HIT:    %s \n", input);
                break;
            } else {
                printf("");
            }
            //if (strncmp(str, "hello", 32 ) == 0) { /*if strncmp finds the word and returns true, print */
            //  printf("%s\n", str);

        }
        //printf("%s\n", str);
        //compareNums(num);
    }
    fclose(fp);
}


void printWordsUtil(int number[], int curr_digit, char output[], int n) {

    // Base case, if current output word is prepared
    int i;
    if (curr_digit == n) {
        //printf("%s ", output);
        isEqual(output);
        return;

    }

    // Try all possible characters for current digit in number[]
    // and recur for remaining digits
    for (i = 0; i < strlen(numbered_letters[number[curr_digit]]); i++) {

        output[curr_digit] = numbered_letters[number[curr_digit]][i];
        printWordsUtil(number, curr_digit + 1, output, n);/* recursive call */


        if (number[curr_digit] == 0 || number[curr_digit] == 1)
            return;
    }
}

// A wrapper over printWordsUtil().  It creates an output array and
// calls printWordsUtil()
void printWords(int number[], int n) {
    char result[n + 1];
    result[n] = '\0';

    printWordsUtil(number, 0, result, n);


}

//Driver program
int main(void) {
    int number[] = {4, 3, 9};
    int n = sizeof(number) / sizeof(number[0]);
    printWords(number, n);
    return 0;
}

使用的文件： 字α(超过420 k字的文件)

感谢您能提供的任何指导！

Answer 1

有几只虫子。

你的前缀功能没问题。你用它替换的strncmp不是。

在第一个单词匹配时停止的命中有一个break，因此没有显示后续的匹配。

在点击时，您打印的是前缀字符串，而不是单词字符串。

我已经用错误注释了你的代码并修复了它们，请原谅不必要的风格清理

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

const char numbered_letters[10][5] = { "", "", "abc", "def", "ghi", "jkl",
    "mno", "pqrs", "tuv", "wxyz"
};

bool
startsWith(const char *pre, const char *str)
{
    size_t lenpre = strlen(pre),
        lenstr = strlen(str);

    return lenstr < lenpre ? false : strncmp(pre, str, lenpre) == 0;
}

void
isEqual(char input[])
{
    int i = 0;
    int ilen = strlen(input);

    // input[strlen(input)] = 0;
// NOTE/BUG: this is extraneous
#if 0
    startsWith(input, input);
#endif
    printf("check:  '%s'\n", input);

    // creating file
    FILE *fp = fopen("words_alpha.txt", "r");
// NOTE/BUG: this needs to be one more to contain the nul terminater
#if 0
    /* Handles largest possible string in the list which is:
        dichlorodiphenyltrichloroethane */
    char str[32];
#else
    char str[33];
#endif

    // fseek(fp, 0, SEEK_SET);
    if (fp == NULL) {
        printf("Error! No file!\n");
    }
    else {
        // printf("Enter a number to be converted into a word-list");
        // scanf("%s", str);

// NOTE/BUG: although feof works here, it is considered _bad_ practice
#if 0
        while (!feof(fp)) {
            fscanf(fp, "%s", str);
#else
        while (1) {
            if (fscanf(fp, "%s", str) != 1)
                break;
#endif

// NOTE/BUG: this is broken
#if 0
            i = strncmp(input, str, 32) == 0;
#endif
// NOTE: this works and is simpler than startsWith (which also works)
#if 0
            i = strncmp(input, str, ilen) == 0;
#endif
#if 1
            i = startsWith(input, str);
#endif

            if (i) {
// NOTE/BUG: we want the actual word to be printed and not just the prefix
#if 0
                printf("HIT:    %s\n", input);
#else
                printf("HIT:    %s\n", str);
#endif
// NOTE/BUG: this break stops on the _first_ word match in the list but we
// want all of them
#if 0
                break;
#endif
            }
            else {
                //printf("");
            }
            // if (strncmp(str, "hello", 32 ) == 0) { /*if strncmp finds the word and returns true, print */
            // printf("%s\n", str);

        }
        // printf("%s\n", str);
        // compareNums(num);
    }
    fclose(fp);
}

void
printWordsUtil(int numbers[], int curr_digit, char output[], int n)
{

    // Base case, if current output word is prepared
    int i;

    if (curr_digit == n) {
        // printf("%s ", output);
        isEqual(output);
        return;
    }

// NOTE: did some cleanup to understand what was going on -- [probably] not a
// bug
    int numcur = numbers[curr_digit];
    const char *letters = numbered_letters[numcur];
    int letlen = strlen(letters);

    // Try all possible characters for current digit in number[]
    // and recur for remaining digits
    for (i = 0; i < letlen; ++i) {
        output[curr_digit] = letters[i];
        printWordsUtil(numbers, curr_digit + 1, output, n); /* recursive call */
        if ((numcur == 0) || (numcur == 1))
            break;
    }
}

// A wrapper over printWordsUtil().  It creates an output array and
// calls printWordsUtil()
void
printWords(int number[], int n)
{
    char result[n + 1];

// NOTE/BUG: this will have garbage in elements 0 to (n - 1)
// NOTE/BUG: result is not used otherwise
    result[n] = '\0';

    printWordsUtil(number, 0, result, n);

}

//Driver program
int
main(void)
{
    int number[] = { 4, 3, 9 };
    int n = sizeof(number) / sizeof(number[0]);

    printWords(number, n);
    return 0;
}