#include <stdio.h>
#include <stdlib.h>
double d[10] = {
1.23, 9.87, 2.23, 2.9, 0.97,
1.45, 5.34, 10.0, 1.801, 5.875
};
int main(void)
{
long loc;
double value;
FILE *fp;
if((fp = fopen("myfile", "wb"))==NULL) {
printf("Cannot open file.\n");
exit(1);
}
/* write the entire array in one step */
if(fwrite(d, sizeof d, 1, fp) != 1) {
printf("Write error.\n");
exit(1);
}
fclose(fp);
if((fp = fopen("myfile", "rb"))==NULL) {
printf("Cannot open file.\n");
exit(1);
}
printf("Which element? ");
scanf("%ld", &loc);
if(fseek(fp, loc*sizeof(double), SEEK_SET)) {
printf("Seek error.\n");
exit(1);
}
fread(&value, sizeof(double), 1, fp);
printf("Element %ld is %f", loc, value);
fclose(fp);
return 0;
}
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