Lecture 21 – Apr 3rd, 2020

Setup

Finish implementing tobin.c such that it reads integers (separated by spaces) from stdin using scanf(3) one at a time and then writes them to the file whose path is the first argument to tobin. (See tobin.c for more details.)
We can use xxd(1) which prints out each byte in hex to examine our result.
```
$ ./tobin output
1 2 3 4 X
$ xxd output
00000000: 0100 0000 0200 0000 0300 0000 0400 0000  ................
```
Notice that it wrote it out in little-endian. I.e., the integer 0x00000001 became the four bytes 01 00 00 00.
Try giving the input 1819043144 1396908143 170996786 X to tobin and take a look at the resulting file.
Finish implementing double.c that reads the file whose path is the first argument to double. The goal is to read in all of the integers, from the file, double them, and then write them back to the file. (See double.c for more details.)
```
$ ./double output
$ xxd output
00000000: 0100 0000 0200 0000 0300 0000 0400 0000  ................
```
Finish implementing frombin.c which reads integers one at a time from a file and prints them to stdout, one per line.
```
$ ./frombin output
2
4
6
8
```
Modify your implementation of frombin.c to first get the file size, then allocate an array of integers long enough to hold the whole file, and then read everything in with a single call to fread(3).