/*
=================================================================
Step 1 (Solution see Step 2)
=================================================================
*/
#include <stdio.h>
void do_averages(FILE* in, FILE* out) {
char line[100];
while (fgets(line, sizeof line, in)) {
float value;
float sum = 0.0f;
int count = 0;
int nchars = 0;
int nc;
while (sscanf(&line[nchars], "%f%n", &value, &nc) == 1) {
sum += value;
++count;
nchars += nc;
}
if (count == 0) return;
fprintf(out, "%f\n", sum/count);
}
}
int main() {
do_averages(stdin, stdout);
return 0;
}
# TODO STEP 1
- Examine the C-program `main.c` and determine what it does.
If you think you understand, predict the output if you compile
the program (see below) and run it from the command line as
`./a.out` nd use the following input:
- `1 2.2 3 4.75 0.05` (all in a single line)
- Understand as the program reads lines in a loop you need to
indicate the end of your input by either typing CTRL-D or with
an empty line (or try some more test inputs).
- Assuming you use the `gcc` directly from a terminal window, will
that source code compile without any modifications if you use
any of the two commands:
- `gcc -xc -std=c89 main.c` (= version of the C language as
standardized by ANSI 1989 and ISO 1990)
- `g++ -xc++ -std=c++23 main.c` (= version of the C++language
as standardized by ISO 33 years later)
REMARK 1:
If you use the CLANG compiler family instead of GCC you may need
to change the compile command to `clang` or `clang++`
respectively.
REMARK 2:
If C++23 is not (yet) supported on your system - or just out of
curiosity - also try some older versions of C++ with `-std=c+20`,
`-std=c++17`, `-std=c++14`, `-std=c++11`, or `-std=c++98`.
-----------------------------------------------------------------
TODO (optional - meant for further self-study only):
- How does the program react to input that is not numeric?
- What needs to be modified if the values read from each input
line are `double`-s instead of `float`-s?
- What needs to be modified if the values read from each input
line are rather `unsigned int`-s instead of `float`-s?
