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#include <stdio.h>
#define SIZE 20
typedef struct _DATA { // My data structure
int a;
double b;
} DATA;
void view_content() // Method to view file content
{
FILE* fptr;
char what[SIZE];
DATA data;
fptr = fopen("testfile.dat", "rb");
fread(what, SIZE, 1, fptr);
fread(&data, sizeof(data), 1, fptr);
fclose(fptr);
printf("%s\na = %d\nb = %f\n\n", what, data.a, data.b);
}
int main()
{
FILE* fptr;
char what[SIZE] = "random access";
DATA data = { 5, 0.2 };
// This part work ok, It writes the data correctly
fptr = fopen("testfile.dat", "wb");
fwrite(what, SIZE, 1, fptr);
fwrite(&data, sizeof(data), 1, fptr);
fclose(fptr);
view_content();
// This part doesn't update the file
fptr = fopen("testfile.txt", "a+b");
fseek(fptr, SIZE, SEEK_SET); // Positions the file pointer
data.a = 10; // New data assigned to be written
data.b = 9.5;
fwrite(&data, sizeof(data), 1, fptr);
fclose(fptr);
view_content();
return 0;
}
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