1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 | #include <stdio.h>
#include <stdlib.h>
#include <stdbool.h>
#include <assert.h>
#include <string.h>
#include <errno.h>
int main(int argc, char* argv[]) {
char const* filename = "write_doubles_with_size.c.bin";
FILE* file = fopen(filename, "r");
if (file != NULL) {
printf("Position is %ld\n", ftell(file));
// read in the length - standard way size is determined
int length;
// when fread/fwrite is called, file position is incremented
fread(&length, sizeof(length), 1, file);
printf("Position is %ld\n", ftell(file));
// read in numbers based on that length
double* numbers = malloc(sizeof(*numbers) * length);
fread(numbers, sizeof(*numbers), length, file);
printf("Position is %ld\n", ftell(file));
// print out the data
for(int i = 0; i < length; i++) {
printf("%f\n", numbers[i]);
}
// free memory
free(numbers);
fclose(file);
} else {
fprintf(stderr, "Failed to open %s:\n%s\n",
filename, strerror(errno));
}
return EXIT_SUCCESS;
}
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