/* Program to show correct storage of floating data by binary i-o */
#include <stdio.h>
#include <math.h>
#include <stdlib.h>
main() {
    float d, e;  FILE *f;
    size_t num_written, num_read;
    d = sqrt(2.0);
    f = fopen("tempfile.dat", "wb");    /* NB: "wb" means "write binary" */
    if (f == NULL) {
        fprintf(stderr, "Failed to open output file\n");
        exit(EXIT_FAILURE);
    }
    num_written = fwrite(&d, sizeof(float), 1, f);
    if (num_written < 1) {
        fprintf(stderr, "Data not written\n");
        fclose(f);
        exit(EXIT_FAILURE);
    }
    fclose(f);
    f = fopen("tempfile.dat", "rb");    /* NB: "rb" means "read binary" */
    if (f == NULL) {
        fprintf(stderr, "Failed to open input file\n");
        exit(EXIT_FAILURE);
    }
    num_read = fread(&e, sizeof(float), 1, f);
    if (num_read< 1) {
        fprintf(stderr, "Data not read\n");
        exit(EXIT_FAILURE);
    }
    fclose(f);
    printf("%f is ", d);
    if (d != e) {
        printf("NOT ");
    }
    printf("equal to %f\n", e);
    return 0;
}