feat: add postfix evaluation algorithm

[kumaryash18]

Description of Change

added postfix expression evaluation algorithm in misc

References

Checklist

• Added description of change
• Added file name matches File name guidelines
• Added tests and example, test must pass
• PR title follows semantic commit guidelines
• I acknowledge that all my contributions will be made under the project's license.

Notes:
A program in C to evaluate postfix expression

[appgurueu]

Your arrays seem small to me (stack size of 10, input size of 25). Also consider using dynamic arrays. I find it quite odd that numbers can only be single characters - something like 45+3- first looks like 45 + 3 - instead of 4 5 + 3 - which it really is.

[kumaryash18]

Your arrays seem small to me (stack size of 10, input size of 25). Also consider using dynamic arrays. I find it quite odd that numbers can only be single characters - something like 45+3- first looks like 45 + 3 - instead of 4 5 + 3 - which it really is.

Hey
I will definitely try to look up in the array size. Reason to use single digit numbers was that it is easy to parse using isdigit() and having more than one digit will just make the expression ambiguous as pointed out. To fix this we can use a delimiter like , as in 45,+,3,-. But in this case parsing might be difficult. Any help is appreciated. @appgurueu

[Panquesito7]

For me, this is looking awesome! 🚀 Thank you for your contribution! 😄👍
@appgurueu, feel free to review this PR and adjust as needed. Thanks. 🙂

[appgurueu]

To fix this we can use a delimiter like , as in 45,+,3,-. But in this case parsing might be difficult. Any help is appreciated. @appgurueu

Yes. I'd recommend a simple space as delimiter. You can do the following (in the loop) then:

// Ignore delimiter
if (post[i] == ' ') continue;
if (isdigit(post[i])) {
	int number = 0;
	do {
		number = number * 10 + (post[i]-'0');
		i++;
	} while (i < strlen(post) && isdigit(post[i]));
	push(number);
	continue;
}

[kumaryash18]

To fix this we can use a delimiter like , as in 45,+,3,-. But in this case parsing might be difficult. Any help is appreciated. @appgurueu

Yes. I'd recommend a simple space as delimiter. You can do the following (in the loop) then:

// Ignore delimiter
if (post[i] == ' ') continue;
if (isdigit(post[i])) {
	int number = 0;
	do {
		number = number * 10 + (post[i]-'0');
		i++;
	} while (i < strlen(post) && isdigit(post[i]));
	push(number);
	continue;
}

Hey
Thanks for your suggestion. I will try to make the required changes as soon as possible because I am busy with some python stuff. If it is possible, can you make the required commits?
Thanks @appgurueu

[Panquesito7]

By the way, looks like your tests aren't made properly 👀 it also doesn't run when I try to run it.

Could you please fix those problems? Let us know if you need any help here or in our Discord server. 😃

[kumaryash18]

By the way, looks like your tests aren't made properly 👀 it also doesn't run when I try to run it.

Could you please fix those problems? Let us know if you need any help here or in our Discord server. 😃

Looks like this is a c++ compiler 👀 . In a C compiler it is working just fine.

[mishraabhinn]

Nice Work @kumaryash18