Reading file using fscanf in C - file-io

Question

I have a fixed format text file to be read in my C program.
The format of the text file is as below:
w 400341a0
r dfcfa8
w 7b034dd4
The first character is always w or r, while the second element is a 32bit hex digit.
I have written the code as below to read this file line by line :
int main (int argc, char *argv[])
{
FILE* file_ptr;
char rw;
uint32_t address;
int file_read;
uint32_t file_line_ctr = 1;
#if(MODE == DEBUG)
{
printf("DEBUG_MODE\n ");
}
#else
{
/*Do Nothing*/
}
#endif
file_ptr = fopen(argv[10], "r");
if (file_ptr == NULL)
{
printf("Can't Open File\n");
}
else
{
printf("File Opened Successfully\n");
}
file_read = fscanf(file_ptr, "%c %x" , &rw, &address);
printf("%c %x \n", rw, address);
while (file_read!= EOF)
{
file_read = fscanf(file_ptr, "%c %x" , &rw, &address);
file_line_ctr ++;
printf("%c %x \n", rw, address);
}
fclose(file_ptr);
printf("File Length = %d \n", file_line_ctr);
return 1;
}
I get the output in the below format for a file with 100000 entries:
w 400341a0
400341a0
r dfcfa8
dfcfa8
w 7b034dd4
7b034dd4
File Length = 200000
Evidently, I am reading the entries twice for some reason, as well as printing them twice.
Can someone figure out why is it so ?

Answer 1

Well. Here is a fix
#include <stdlib.h>
#include <stdio.h>
int main (int argc, char *argv[])
{
FILE* file_ptr;
char rw;
unsigned int address;
int file_read=0;
unsigned int file_line_ctr = 1;
#if(MODE == DEBUG)
{
printf("DEBUG_MODE\n ");
}
#else
{
/*Do Nothing*/
}
#endif
file_ptr = fopen(argv[1], "r");
if (file_ptr == NULL)
{
printf("Can't Open File\n");
}
else
{
printf("File Opened Successfully\n");
}
/*
file_read = fscanf(file_ptr, "%c %x " , &rw, &address);
printf("%c %x \n", rw, address);
*/
while (true)
{
file_read = fscanf(file_ptr, "%c %x " , &rw, &address);
if (file_read == EOF)
break;
file_line_ctr ++;
printf("%c %x \n", rw, address);
}
fclose(file_ptr);
printf("File Length = %d \n", file_line_ctr);
return 1;
}
You will notice that I have added a space after the %x to eat the newlines as white space.
I have also modified your while loop a little to stop the last line being repeat printed. Crude. But it will work until you can rethink the logic. The while (true) may not work with all compilers. I used while (1). Which is non standard but worked for me.