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Hi,
I was wondering, in the standard libraries, is there an integral counterpart to the "double pow(double, double)" function? (for an integer raised to the power of a positive integer)
I am asking this because I want to use the pow function without having to worry about everything associated with floating points (precision etc).
Thank you very much.
Unfortunately no, only versions for float, double and long double.Quote:
I was wondering, in the standard libraries, is there an integral counterpart to the "double pow(double, double)" function? (for an integer raised to the power of a positive integer)
Thankfully, it is much easier to write a version for an int raised to an int, so you could always write it yourself.Quote:
I am asking this because I want to use the pow function without having to worry about everything associated with floating points (precision etc).
thank you for your reply.
Can you please enlighten me a bit on that? It doesn't sound too easy to me. Unless the most efficient way is to just loop through the exponent?Quote:
Thankfully, it is much easier to write a version for an int raised to an int, so you could always write it yourself.
Thank you very much
An efficient yet easy way (not sure if it is the most efficient) is to note that:Quote:
Unless the most efficient way is to just loop through the exponent?
For a integers x, n and letting ^ denote exponentiation:
x^(2n) = x^n * x^n
x^(2n+1) = x^n * x^n * x
Consequently, one could write a recursive function that performs this calculation.
hmm I see... I will try to implement that.Quote:
An efficient yet easy way (not sure if it is the most efficient) is to note that:
For a integers x, n and letting ^ denote exponentiation:
x^(2n) = x^n * x^n
x^(2n+1) = x^n * x^n * x
Thank you for your help
It doesn't need to be recursive:Code:unsigned int pow(unsigned int a, unsigned int b) {
unsigned int result = 1;
while (b) {
if (b & 1)
result *= a;
b >>= 1;
a *= a;
}
return result;
}