I am writing a C program in Ubuntu operating system. I provide an input text file containing string of characters.The program is required to read and manipulate ONE CHARACTER at time and print the whole content of input file in reverse.
When I compile program, I get following error:
reverseFileContent.c: In function ‘main’:
reverseFileContent.c:51:16: warning: passing argument 1 of ‘feof’ makes pointer from integer without a cast [-Wint-conversion]
while(!feof(inputFile))
Can you please explain the error message to me.
Below is the program:
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#define BUFFER_SIZE 256
int main (int argc, char *argv[]){
FILE *inputFile, *outputFile;
int fileSize;
int pointer;
char buffer[BUFFER_SIZE];
/* Check for correct user's inputs. */
if( argc !=3 ) {
fprintf(stderr, "USAGE: %s inputFile outputFile.\n", argv[0]);
exit(-1);
}
/* Make sure input file exists. */
if( (inputFile = fopen(argv[1], O_RDONLY))) {
fprintf(stderr, "Input file doesn't exist.\n");
exit(-1);
}
/* Create output file, if it doesn't exist. Empty the file, if it exists. */
if((outputFile = fopen(argv[2], "a+"))) {
fclose(inputFile);
exit(-1);
}
/* Find the size of the input file. */
fileSize = fseek(inputFile, 0, SEEK_END);
/* Read input file and write to output file in reversed order.
* Use lseek() to move the file pointer to the ith position.
* To set the file pointer to a position use the SEEK_SET flag in lseek().
*/
for(pointer=fileSize-1; pointer>=0; pointer--) {
/* INSERT YOUR CODE HERE */
/*
* In a loop:
* - Read input file into a buffer
* Don't read one byte at a time! Try to read BUFFER_SIZE (i.e., 256) bytes at a time.
* - Write content in the buffer to the output file
*/
while(!feof(inputFile))
{
fgets(buffer, BUFFER_SIZE, inputFile); //reads 256 bytes at a time
fputs (buffer , outputFile );
}
}
fclose(inputFile);
fclose(outputFile);
return(0);
}
