Question

How to read the first double value twice from binary file in C

Answer 1

#include <stdio.h>

int main(void)
{
    const char* filename = "d:\\date.bin";

    double d1 = 627.9182;
    FILE* fp = fopen(filename, "wb");
    fwrite(&d1, sizeof d1, 1, fp);
    fclose(fp);

    fp = fopen(filename, "rb");
    double d2;
    fread(&d2, sizeof d2, 1, fp);
    printf("%lf\n", d2);

    fpos_t pos = 0;
    fsetpos(fp,&pos);

    double d3;
    fread(&d3, sizeof d3, 1, fp);
    printf("%lf\n", d3);

    fclose(fp);
}




/*
run:

627.918200
627.918200

*/

 

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