CODEWITHSUNDEEP
carrayschar
Gary M
Gary M

Reputation: 177

Reading text file into char array

I'm having some trouble getting text into a char array. It worked fine when I set a static size for the array like

char speech[15000];

but that was inefficient so I tried using calloc instead. That made it stop working. The array exists at the right size, but nothing gets written in. Here's the relevant code. What am I doing wrong?

int main() {

FILE* inFile;
int i;
int count = 0;

printf("\nOpening file April_30_1789.txt\n");

inFile = fopen("./speeches/April_30_1789.txt", "r");

if(inFile == NULL) {
    printf("Could not find April_30_1789.txt\n");
    return -1;
}

char ch;

while((ch = fgetc(inFile) != EOF)) count++;

rewind(inFile);

int size = count;

printf("Size of the array is %d\n", size);

char *speech = (char *)malloc(size*sizeof(char) + 1*sizeof(char));

fscanf(inFile, "%s", speech);

printf("Closing the file.\n");
fclose(inFile);

printf("%s", speech);

printf("\n\nDone\n");

return 0;

}

Currently, this gives me

Opening file April_30_1789.txt
Size of the array is 8617
Closing the file.
Fellow-Citizens

Done

Upvotes: 2

Views: 24646

Answers (3)

Chnossos
Chnossos

Reputation: 10496

Possible duplicate of Reading the whole text file into a char array in C.

Your problem : fscanf with the "%s" format will read up to the first whitespace encountered.

Possible solution (error-checking is omitted for conciseness) :

#include <stdio.h>  /* printf */
#include <stdlib.h> /* fopen, fseek, ... */

char *buffer = NULL;
size_t size = 0;

/* Open your_file in read-only mode */
FILE *fp = fopen("your_file_name", "r");

/* Get the buffer size */
fseek(fp, 0, SEEK_END); /* Go to end of file */
size = ftell(fp); /* How many bytes did we pass ? */

/* Set position of stream to the beginning */
rewind(fp);

/* Allocate the buffer (no need to initialize it with calloc) */
buffer = malloc((size + 1) * sizeof(*buffer)); /* size + 1 byte for the \0 */

/* Read the file into the buffer */
fread(buffer, size, 1, fp); /* Read 1 chunk of size bytes from fp into buffer */

/* NULL-terminate the buffer */
buffer[size] = '\0';

/* Print it ! */
printf("%s\n", buffer);

Upvotes: 10

nikola-miljkovic
nikola-miljkovic

Reputation: 670

as pmg said while((ch = fgetc(inFile) != EOF)) count++; makes your file pointer point at the end, use rewind(FILE* fileptr); to return to beginning of file.

Upvotes: 1

P0W
P0W

Reputation: 47844

Your file pointer inFile is pointing to end

I'd do something like following :

long lSize;

fseek( inFile , 0L , SEEK_END); //use the function instead
lSize = ftell( inFile );       // to know the file size
rewind( inFile );             // Now point to beginning 

char* speech = calloc( 1, lSize+1 );
if( speech )
{
    if( fread( speech , lSize, 1 , inFile) != 1)
    {
      fclose(inFile) ;
      free(speech); 
      exit(1);
    }
}

// Process the speech Here


fclose(inFile); 
free(speech); // Don't forget to free the allocated memory !

Upvotes: 1

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