如何读取用户输入的字符串并进行分配？

Question

So I've been working on this code for a while now and I can't figure out why it's not working. Basically I'm suppose to create a program using functions to read in string input from the user which is the filename for “data.txt”. I need a function to determine the number of rows that are in the file in order to allocate an array of character pointers. Then my program should print out the strings read from the file. Finally the program should free the allocated memory.

This is my non-working code.

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

#define MAX_WIDTH 144

void getFileName(char* array1);
int getLineCount(FILE* data, int max);
char** createArryOfPtrs(int rows);
int main(void) 
{
  int max = 0;
  int rows;
  char array1[MAX_WIDTH];
  FILE* data = fopen(array1, "r");
  getFileName(array1);
  getLineCount(data, max);
  createArryOfPtrs(rows);


  fclose(data);
  return 0;
}

void getFileName(char* array1)
{
  printf("Enter filename: ");
  fscanf(stdin, "%144[^\t]", array1);

}

int getLineCount(FILE* data, int max)
{
  int i = 4;
  char *array1[MAX_WIDTH];
  if(data != NULL)
  {
    while(fgets(*array1, MAX_WIDTH, data) != NULL)
    {
      i+=1;
    }
  }


return i;
}

char** createArryOfPtrs(int rows)
{
  int r = 4, c = 9, i, j, count;
  char *array1[r];
  for(i =0; i < r; i++)
  {
    array1[i] = (char*)malloc(c * sizeof(char));
  }
  count = 0;
  for(i = 0; i < r; i++)
  {
    for(j = 0; j < c; j++)
    {
      array1[i][j] = ++count;
    }
  }

  for(i = 0; i < r; i++)
  {
    for(j = 0; j < c; j++)
    {
      printf("%c", array1[i][j]);
    }
  }

  return 0;
}

This is the text file.

larry snedden 123 mocking bird lane
sponge bob 321 bikini bottom beach
mary fleece 978 pasture road
hairy whodunit 456 get out of here now lane

I'm still new to C so I'm very confused. Appreciate any help I can get.

Answer 1

Order matters! You get the name of the file to open after you call fopen . That means the data in array1 will be uninitialized and indeterminate (and seem random).

You need to read the name of the file first .

This issue should have been very clear if you did a little rubber duck debugging .