c - 如何在C中将一个字符变成一个单词

Question

我目前正在从一个文件中收集输入，但我的程序将每个字母而不是每个单词分隔到 char 数组中。如何更改我的代码以获取每个单词？

char c, fileName[20];
FILE *f;

void getFile() {    
    f = fopen(fileName, "r");

    while((c = fgetc(f)) != EOF) {
        printf("%c",c);
    }
    fclose(f);
}

Answer 1

您可以将扫描集与 fscanf 或 sscanf 一起使用。此扫描集 %29[a-zA-Z] 读取小写和大写英文字符，并在遇到不在集合中的字符时停止。 29 限制了要读取的最大字符数，以免覆盖缓冲区 word[30]。当 fscanf 失败时，else 将从文件中读取一个字符并让 fscanf 再次尝试读取另一个单词。
这也是使用命令行传入文件读取为argv[1]。

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

int main( int argc, char *argv[])
{
    char word[30] = {'\0'};
    int ch = 0;
    FILE *pf = NULL;

    if ( argc != 2) {//command requires program name and a file name
        printf ( "useage: program filename\n");
        return 1;
    }

    if ( ( pf = fopen ( argv[1], "r")) == NULL) {
        perror ( "could not open file");
        return 1;
    }

    while ( 1) {
        if ( ( fscanf ( pf, "%29[a-zA-Z]", word)) == 1) {
            printf ( "%s\n", word);
        }
        else {
            if ( ( ch = fgetc ( pf)) == EOF) {//read one character and check for end of file
                break;
            }
            //could do something here with the value of ch if needed
        }
    }
    printf ( "--DONE--\n");

    return 0;
}

这将为每个单词分配一个数组。添加单词时，使用 realloc 扩展数组。

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

int main( int argc, char *argv[])
{
    char **words = NULL;//pointer for words
    char **temp = NULL;
    char word[30] = {'\0'};
    int ch = 0;
    int each = 0;
    int found = 0;
    int count = 0;
    int wordsize = 0;
    FILE *pf = NULL;

    if ( argc != 2) {//command requires program name and a file name
        printf ( "useage: program filename\n");
        return 1;
    }

    if ( ( pf = fopen ( argv[1], "r")) == NULL) {
        perror ( "could not open file");
        return 1;
    }

    while ( 1) {
        if ( ( fscanf ( pf, "%29[a-zA-Z]", word)) == 1) {
            found = 0;
            for ( each = 0; each < wordsize; each++) {
                if ( strcmp ( words[each], word) == 0) {
                    found = 1;
                    break;
                }
            }
            if ( found == 0) {
                wordsize += 1;// increment number of words
                temp = realloc ( words, wordsize * sizeof ( char *));//reallocate for another word
                if ( temp != NULL) {
                    words = temp;
                    words[wordsize - 1] = malloc ( strlen ( word) + 1);//malloc for the word itself
                    if ( words[wordsize - 1] != NULL) {
                        strcpy ( words[wordsize - 1], word);
                    }
                    else {
                        printf ( "malloc failed\n");
                        wordsize -= 1;
                        break;
                    }
                }
                else {
                    printf ( "realloc failed\n");
                    wordsize -= 1;
                    break;
                }
            }
            printf ( "%s\n", word);
        }
        else {
            if ( ( ch = fgetc ( pf)) == EOF) {//read one character and check for end of file
                break;
            }
            //something could be done with ch if needed
        }
    }
    printf ( "--DONE Reading file--\n");
    for ( each = 0; each < wordsize; each++) {// print each word
        printf ( "%s\n", words[each]);
    }
    count = 0;
    printf ( "Enter a word to search for\n");
    if ( ( scanf ( "%29[a-zA-Z]", word)) == 1) {
        for ( each = 0; each < wordsize; each++) {
            if ( strcmp ( words[each], word) == 0) {
                printf ( "Found %s at index %d\n" word, each);
                count++;
            }
        }
        printf ( "Found %s %d times\n" word, count);
    }
    for ( each = 0; each < wordsize; each++) {//release memory
        free ( words[each]);
    }
    free ( words);


    return 0;
}