# Binary I/O (Answers)

Here is some additional practice using binary I/O. Some of these might take a little bit of thinking, but this practice is here to help you get more comfortable with the material.

Assume big-endian notation.

1. Letâ€™s start this off simple. Suppose that an `int` created in C is 4 bytes (32 bits) in size. How would the integer `2` be stored in binary in memory?

Answer: `00000000 00000000 00000000 00000010`

1. Given the previous answer, if a hypothetical program was written to write the integer `2` in binary to a file, what data would be in the file? Write your answer in binary.

Answer: `00000000 00000000 00000000 00000010`

1. Given the following program, what would `output.bin` contain after execution? Again, write your answer in binary. Assume all necessary libraries are included and all files are opened/closed properly.
``````struct cool_struct
{
int x;
};

int main(void)
{
struct cool_struct basically_just_an_int;
FILE *ofp = fopen("output.bin", "wb");

basically_just_an_int.x = 2;

fwrite(&basically_just_an_int, sizeof(struct cool_struct), 1, ofp);

fclose(ofp);

return 0;
}``````

Answer: `00000000 00000000 00000000 00000010`