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VSMechatronics/Lectures/LC19/WriteHeaderArrayAndUpdate.c

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2022-04-07 15:58:01 +00:00
#include <stdio.h>
#include <stdlib.h>
struct MyStruct
{
int NoItems;
int max;
float average;
};
int main()
{
struct MyStruct MyRecord;
FILE *fptr;
int ArrayData[100];
int items = 0;
int sum = 0;
int i;
/* Write this file to disk - binary format, usual error checking */
fptr = fopen ("strdata.dat","wb");
if ( fptr == NULL )
{
printf ("\nError creating file - aborting ");
exit (0);
}
/* Pop some dummy data into our structure */
MyRecord.NoItems = 0;
MyRecord.max = 0; ;
MyRecord.average = 0;
/* This line does the writing of the structure */
fwrite ( &MyRecord, sizeof(struct MyStruct), 1, fptr);
/* Populate the array */
for ( i = 0 ; i < 100 ; i++)
{
ArrayData[i] = i;
if ( ArrayData [i] > MyRecord.max)
MyRecord.max = ArrayData[i];
sum = sum + ArrayData[i];
items++;
}
/* This line does the writing of the Array */
fwrite ( &ArrayData[0], sizeof(int),100, fptr);
/* Update the values in the structure */
MyRecord.NoItems = items;
MyRecord.NoItems = (float)sum / (float)items;
/* rewind the file to write the structure again */
fseek(fptr, SEEK_SET, 0);
rewind (fptr);
/* This line does the writing of the structure */
fwrite ( &MyRecord, sizeof(struct MyStruct), 1, fptr);
/* And close */
fclose (fptr);
/* To read the data we would use */
fptr = fopen ("strdata.dat","rb");
if ( fptr == NULL )
{
printf ("\nError opening input file - aborting ");
exit (0);
}
/* This line does the reading */
fread ( &MyRecord, sizeof(struct MyStruct), 1, fptr);
printf ("No. items in the file = %d", MyRecord.NoItems);
printf ("Maximum = %d", MyRecord.max);
printf ("Average is = %.2f", MyRecord.average);
/* And close */
fclose (fptr);
/* All Done */
return 0;
}