将字符串复制到结构数组的元素

Question

我正在尝试复制一个 C 字符串，该字符串是从一个文件中读入的到一个结构数组的一个元素中，但它不是在复制。当我尝试打印时，这个词不存在。我对 C 有点陌生。下面是我的代码。非常感谢您的帮助。

typedef struct Tree{
    int numTimes; //number of occurrences
    char* word; //the word buffer
}Node;

#include "proj2.h"
#include <ctype.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>

int main(int argc, char* argv[]){

    FILE* readIn; //read file pointer
    FILE* writeOut; //write file pointer
    char buffer[18]; //allocate buffer ***please do not fuzz
    int length = 0;
    int count = 0;
    Node* array = (Node*) malloc(sizeof(Node));

    /*if(argc < 3){ //if the number of command line arguments is < 3, return EXIT_FAILURE
     return EXIT_FAILURE;
     }*/
    argv[1] = "/Users/magnificentbastard/Documents/workspaceCPP/proj2/Password.txt"; //****testing
    argv[2] = "outFile.txt"; //****testing

    readIn = fopen(argv[1], "r"); //opens the selected argument file for reading
    writeOut = fopen(argv[2], "w"); //opens the selected argument file for writing

    if(readIn == NULL){ //if there
        printf("ERROR: fopen fail.\n");

        return EXIT_FAILURE; //exits if the file opens
    }

    while(fscanf(readIn, "%18s", buffer) == 1){ //loop to read in the words to the buffer
        count++; //counts the words coming in
        modWord(buffer); //modifies the words coming in

        array = (Node*)realloc(array, sizeof(Node));

        for(int i = 0; i < count; i++){ //****not copying over...HELP
            strcpy(array[i].word, buffer);
        }
    }

    //Node array[count];
    fprintf(stderr, "%d ", count); //***for testing purposes only
    int elements = sizeof(array)/sizeof(array[0]); //***testing assigns num elements
    fprintf(stderr, "%d ", elements); //***testing prints num elements

    fclose(readIn); //closes the in-file
    fclose(writeOut); //closes the out-file

    return EXIT_SUCCESS;
}

Answer 1

array[count] 不分配内存。我相信您在这里尝试实现的是single-linked list of strings。

您尝试做的事情可以实现，但您需要使用 malloc/free 组合为 array 分配内存。更重要的是，您想要实现的目标应该是通过将 Node.word 设为固定大小的数组或指针并逐个节点分配内存。

无法通过使用 sizeof 运算符检索数组的长度，因为 sizeof 在编译中进行评估，并且它始终会返回您平台上指针的大小。