Hi in my project I've to read a .bin file which has sensor data in the form of short(16 bit values)
. I'm doing this using fread
function into a buffer, but I feel that the reading-in is not happening correctly. I mean there is no consistence between what I write and what I read in. Can you guys suggest what is going wrong here? This is not my code from my project... I'm only trying to verify the fread
and fwrite
functions here.
#include<stdio.h>
void main()
{
FILE *fp = NULL;
short x[10] = {1,2,3,4,5,6,5000,6,-10,11};
short result[10];
fp=fopen("c:\\temp.bin", "wb");
if(fp != NULL)
{
fwrite(x, 2 /*sizeof(short)*/, 10 /*20/2*/, fp);
rewind(fp);
fread(result, 2 /*sizeof(short)*/, 10 /*20/2*/, fp);
}
else
exit(0);
printf("\nResult");
printf("\n%d",result[0]);
printf("\n%d",result[1]);
printf("\n%d",result[2]);
printf("\n%d",result[3]);
printf("\n%d",result[4]);
printf("\n%d",result[5]);
printf("\n%d",result[6]);
printf("\n%d",result[7]);
printf("\n%d",result[8]);
printf("\n%d",result[9]);
fclose(fp)
}
After I do the fread() (HEX values):
temp.bin:
01 02 03 04 05 06 e1 8e 88 06 ef bf b6 0b...
After I do the fwrite()
stdout:
Result
0
914
-28
-28714
-32557
1
512
-32557
908
914
Open the file with mode w+
(reading and writing). The following code works:
#include<stdio.h>
int main()
{
FILE *fp = NULL;
short x[10] = {1,2,3,4,5,6,5000,6,-10,11};
short result[10];
int i;
fp=fopen("temp.bin", "w+");
if(fp != NULL)
{
fwrite(x, sizeof(short), 10 /*20/2*/, fp);
rewind(fp);
fread(result, sizeof(short), 10 /*20/2*/, fp);
}
else
return 1;
printf("Result\n");
for (i = 0; i < 10; i++)
printf("%d = %d\n", i, (int)result[i]);
fclose(fp);
return 0;
}
With output:
Result
0 = 1
1 = 2
2 = 3
3 = 4
4 = 5
5 = 6
6 = 5000
7 = 6
8 = -10
9 = 11