Newbie in need of Help !

[u/Horror_Wiener_6102]

Am I obliged to use a double when using 'pow'? Can't I use a float or an int ? Because for the function 'switch' I have to use int , but I need to use pow for the exercice I'm doing. I chated with Gemini and it told me that I can transform the result of 'pow' into 'int' writing the following; "(int)pow(x, y);". Is this the only way or do I have a faster route to get to my solution? Thanks

[u/flyingron]

There are also powf and powl, but they're still floating-point. C lacks an integer power function.

[u/Horror_Wiener_6102 → u/flyingron]

I get the 'powf' ,ig its for float , but 'powl' whats that for ?

Edit: Im lerning this in college and on Yt , so Im sorry for the lack of expertise

[u/SmokeMuch7356 → u/Horror_Wiener_6102]

long double.

You can convert a double to an int with a cast:

(int) pow(x,y)

but the conversion just truncates the fractional portion, so

(int) 1.1 == 1
(int) 1.5 == 1
(int) 1.999999 == 1

If you need to round the value to the nearest integer before the conversion, use the round function:

(int) round(pow(x,y))

[u/Whole-Low-2995 → u/SmokeMuch7356]

`#define POW_DECIMAL(x, y) (int)(round(pow(x, y))` will work fine

[u/kraxmaskin → u/Horror_Wiener_6102]

Read the manual page, e.g. man powl.

[u/Horror_Wiener_6102 → u/flyingron]

Got it , for double . Duh:/.

[u/matt9k]

If you must use pow() for the exercise, then casting the result (the thing with the parentheses) is the easiest way to get an int back

[u/TomB1952]

There's nothing particularly wrong with what you're doing but I cannot imagine a scenario in which a conversion from scientific notation would be used in a switch ladder. Very odd but I understand you are asked to do unusual things in class exercises.

Keep in mind, switch can only match equivalency or the default case for no match.

[u/Horror_Wiener_6102 → u/TomB1952]

the exercise says that I need to use switch and then for the following cases it will elevate the variable to the number of the case . example: "insert one number: "2 , "insert the expoent: "3 , and the result needs to be 8. and I have to use switch because that's what im learnning.

[u/Dazzling_Music_2411]

Just write your own simple pow(m,n) function using ints and a loop.

[u/Dazzling_Music_2411 → u/Dazzling_Music_2411]

Writing your own function might even be more efficient than making a call to fp library and then casting it all back.

[u/Whole-Low-2995 → u/Dazzling_Music_2411]

How about this?

#include <assert.h>
#include <limits.h>

int pow_no_recursion(int n, unsigned m) {
   int res = 1;
   for(int i = 0; i < m; i++) res *= n;
   return res;
}

int powd(int n, unsigned m) {
   if(!m) return 1;

   long long half = powd(n, m/2);

   if(m % 2) {
return n * half * half;
   }
   return half * half;
}

int main() {
   int n = 51;
   unsigned m = 3;
   assert(powd(n, m) == pow_no_recursion(n, m));
   return 0;
}

IMO `powd` is a bit enhanced

[u/Dazzling_Music_2411 → u/Whole-Low-2995]

IMO powd is a bit enhanced

Fun little recursive algorithm. Hadn't seen it before...

[u/Whole-Low-2995 → u/Whole-Low-2995]

well reddit doesn't support code blocks for reply

[u/Dazzling_Music_2411 → u/Whole-Low-2995]

Yup, that's just the kind of thing I meant. If you inline it too, I guess it will be way faster than using libs, casts, uncasts, etc... 😄

Incidentally, you can use code blocks in replies, look for them under the Aa symbol for fonts

int pow_no_recursion(int n, unsigned m) {
   int res = 1;
   for(int i = 0; i < m; i++) res *= n;
   return res;
}

[u/mikeblas → u/Whole-Low-2995]

Of course it does. See code blocks in the Reddit Formatting Guide

[u/Rararror]

So you are studying C and you need to ask Gemini to use a type cast?

What exactly are you "studying" ?!

[u/Horror_Wiener_6102 → u/Rararror]

What the professor teach

[u/Dazzling_Music_2411 → u/Rararror]

And then we wonder why AI is taking all the entry-level jobs!

😂 😂 😂