c - 返回指向字符串数组的指针 C

Question

我正在尝试返回一个从文件中获取的字符串数组。该文件看起来像这样(第一行是单词数，每一行都是单词)。当功能结束时，我在主要部分得到一些奇怪的输出。我想返回指向字符串数组的指针。请注意，使用打印的部分代码用于检查我的程序。

这是分配内存的函数:

char *generisiProstor(int n) {
    return (char*)malloc(n*sizeof(char[20])); 
}

这是从 rijeci.txt 中获取单词的函数，应该返回指向包含单词的字符串数组的指针:

char* ucitajRijeci(int n) {

    char  i;
    char *rijeci;

    static const char filename[] = "rijeci.txt";
    FILE *file;
    file = fopen(filename, "r");
    if (file != NULL)
    {
        char line[20];
        int n;
        fscanf(file, "%d", &n);
        rijeci = generisiProstor(n);
        if (rijeci == NULL) { 
            return NULL;
        }
        int i = -1;

        fgets(line, 20, file);        //skipping first line witch is integer and not needed
        while (fgets(line, 20, file) != NULL) 
        {
            printf("%s\n", line);            //normal output
            i++;
            strcpy(rijeci + i, line);
            printf("%s\n", rijeci + i);     //normal expected output
        }
        for (i = 0; i < n; i++) {
            printf("%s\n", rijeci + i);   //wrong output
        }
    }
    return rijeci;
}

主要

int main()
{
    static const char filename[] = "rijeci.txt";
    FILE *file;
    file = fopen(filename, "r");
    char *rijeci;
    int i;
    if (file != NULL)
    {
        char line[20];
        int n;
        fscanf(file, "%d", &n);
        rijeci = ucitajRijeci(n);
        printf("Here is the array: ");
        for (i = 0; i < n; i++) {
            printf("%s ", rijeci+i);  //wrong output
        }
    }
    return 0;
}

Answer 1

这里必须使用二维数组(char ** 而不是 char *)。由于您要返回二维数组，因此您必须将 rijeci 声明为 char **rijeci;

1. 两个函数的返回类型也应该是char **。
2. 将 rijeci + i 更改为 rijeci[i]。
3. 正确的代码缩进。

试试这个修改后的代码。这将起作用:-

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

/* generisiProstor */

char **generisiProstor(int n)
{
    char **c; // making 2-d array
    c = (char **)malloc(n * sizeof(char *));
    for (int i = 0; i < n; i++)
    {
        c[i] = (char *)malloc(20 * sizeof(char));
    }
    return c;
}

/*  ucitajRijeci  */

char **ucitajRijeci(int n)
{

    char **rijeci; // change to char **

    static const char filename[] = "rijeci.txt";
    FILE *file;
    file = fopen(filename, "r");
    if (file != NULL)
    {
        char line[20];
        int n;
        fscanf(file, "%d", &n);
        rijeci = generisiProstor(n);
        if (rijeci == NULL)
        {
            return NULL;
        }
        int i = -1;

        fgets(line, 20, file); //skipping first line witch is integer and not needed
        while (fgets(line, 20, file) != NULL)
        {
            printf("%s\n", line); //normal output
            i++;
            strcpy(rijeci[i], line);
            printf("%s\n", rijeci[i]); //changed to rijeci[i]
        }
        for (i = 0; i < n; i++)
        {
            printf("%s\n", rijeci[i]); //changed to rijeci[i]
        }
    }
    return rijeci;
}

/*  main()  */

int main()

{

    static const char filename[] = "rijeci.txt";
    FILE *file;
    file = fopen(filename, "r");
    char **rijeci; // change to char **
    int i;
    if (file != NULL)
    {
        char line[20];
        int n;
        fscanf(file, "%d", &n);
        rijeci = ucitajRijeci(n);
        printf("Here is the array: ");
        for (i = 0; i < n; i++)
        {
            printf("%s ", rijeci[i]); //changed to rijeci[i]
        }
    }
    return 0;
}