CODEWITHSUNDEEP
carraysstructc-stringsstrcpy
user5924094
user5924094

Reputation:

Copy string to element of struct array

I'm attempting to copy a C-string, which is read in from a file to an element of a struct array, but it is not copying. When I attempt to print, the word is not there. I'm kind of new to C. Below is my code. Many thanks for your help.

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;
}

Upvotes: 0

Views: 152

Answers (1)

orhtej2
orhtej2

Reputation: 2165

array[count] doesn't allocate the memory. I believe what you're trying to implement here is single-linked list of strings.

What you're trying to do can be achieved, but you'd need to allocate memory for array by using malloc/free combo. What's more, what you're trying to achieve should by done by either making Node.word an array of fixed size OR a pointer and allocating the memory on Node-by-Node basis.

Length of an array cannot be retrieved by use of sizeof operator as sizeof is evaluated in compile and it'll always return a size of a pointer on your platform.

Upvotes: 1

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