Write your own math program for FreeDOS

With a little programming, you can create your own tools to expand the command line. Let's see how to write your own math program for FreeDOS, to do basic arithmetic operations.

*Apologies for the sound issues on this one. I recorded it immediately after last week's video, and I didn't realize my sound setup was causing issues. I'll fix it for the next video.

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Standard comment rules apply.

[sharoyveduchi]

It's unfortunate there are audio issues (brief moments where audio gets cut off) but this video was very informative. Thank you. I'm tempted to write my own.

[ahmad-murery]

It's always a happy day when it starts with a retro programming session, it makes me think simpler and relaxes my brain muscles.
Thanks Jim,

[Flora-nggt]

❤Freedos The best Power
System❤Brazil❤

[OpenGLever]

Even when atof does transform a string into the value 0 dot 0 you should check if the string given is a number with isdigit from ctype header.

[joeshmoe]

I'm wondering if the data type on a separate line before function name is just old convention or if this compiler needs that?

[OpenGLever]

Why don't you use the *default* clause inside the switch statement for the unrecongnized operation? I would assume, that the compiler can optimize it better, when you use a default clause, instead of writing the default message outside of the switch statement.

[DV-yexb]

Hey i wrote this program to practice c the program tells a person how many boxes he can buy depending how much money the person has what do you think is there anything that can make this code better?

#define BOX 6
Int main() {
double dollars;
double cost;

printf("a box is $6 how many dollars do you have? ");
scanf("%lf", dollars);

cost = dollars / BOX;
printf("you can buy %lf boxes", cost);

return 0;
}

[ernietech-]

Someday I'll buckle down and learn C++.

[SlideRSB]

Instead of returning 0 for invalid operations and division by zero, wouldn't it be more appropriate to return NaN?

[davemurey]

Очень хороший бесплатный компилятор - Free Pascal, имеет мощную IDE. Зачем этот C? Только если вы предпочитаете этот язык?

[joeshmoe]

If I ever get rich, I'm giving you 500K to make a modern DOS 64-bit, VESA graphics, Gigs of RAM, built in networking, no extenders, etc. I know, i know, here I am again. I'm telling you, there's a huge hole in the market for a debloated, stable, simple OS that works like DOS. Imagine banking systems, military, etc. Do they want to use windows? Probably not. Forced updates, instability, copious background processes constantly accessing the disk, so a power outage could result in corruption. Then there's Linux/Unix which is too complex and convoluted. Seeing hi-res text mode apps would be beautiful. It'd be like what we thought the future would look like in the 80s.
I wish I was a smarter programmer, cause I would make it. I was stuck with real mode back when I tried to make my own OS. If you think it's a decent idea, you could let other programming friends know.