[SOLVED] c programming function variable ...

pan64 · 04-30-2023, 01:35 AM

Quote:

Originally Posted by NevemTeve

https://en.m.wikipedia.org/wiki/Comma_operator
Counting the commas it slow and not universal solution. How about using an array?

Code:

{
    long long arr[] = { values };
    size_t narr= (sizeof arr)/(sizeof arr[0]);
    maxval= maxfun (narr, arr);
}

That's what I already told, we can use the original argv array, do not need to do anything with it.

Code:

int check_argument(char *s) {
   returns int if can be converted to int
   returns INT_MIN in case of any problem
}
int max_val=INT_MIN
for (int i=0; i<argc; i++) {
    val=check_argument(argv[i])
    if (val>max_val) {
      max_val=val
    }
}
return max_val

This is just a non-working skeleton or just an idea to work with.

NevemTeve · 04-30-2023, 06:55 AM

As a macro:

Code:

#define LLMAX(into,...) \
do { \
    long long arr[] = { __VA_ARGS__ }; \
    size_t narr= (sizeof arr)/(sizeof arr[0]); \
    maxval= llmaxfun (narr, arr); \
} while(0)

Racho · 04-30-2023, 06:57 AM

Quote:

Originally Posted by NevemTeve

https://en.m.wikipedia.org/wiki/Comma_operator
Counting the commas it slow and not universal solution. How about using an array?

Code:

{
    long long arr[] = { values };
    size_t narr= (sizeof arr)/(sizeof arr[0]);
    maxval= maxfun (narr, arr);
}

Yup, using an array is the way. And it lets casting the arguments!

I have this piece of code that meets the initial requirements:
- It has to work with long long int
- Don't tell the function how many arguments you are passing to it

And now I think it works fine:

Code:

#include <stdio.h>
#include <limits.h>

long long int llin_max(int num_args, long long int* args) {
	int i=0;
	long long int max, new_num;
	max = LLONG_MIN;
	for (i=0; i < num_args; i++) {
		max = max > args[i]? max : args[i];
	}

	return max;
}

#define countparams(...)  sizeof( (long long int[]) { __VA_ARGS__}  ) / sizeof(long long int)
#define lli_max(...) llin_max(countparams(__VA_ARGS__), (long long int[]) {__VA_ARGS__})

int main() {
	long long int num=0;
	long long int a = 5000, b = 77500, c = -583;
	int inta = 5000, intb = 977500, intc = -583;

	num = lli_max(a, b, c);	
	printf("The greatest number is: %lli\n", num);

	num = lli_max(inta, intb, intc); 
	printf("The greatest number is: %lli\n", num);
	
	num = lli_max((5,6),(7,11),2,(50,3));	// Now this works
	printf("The greatest number is: %lli\n", num);

	return 0;
}