power and exponential functions help (forloops)

[aznrurouni]

was wondering if anybody knew how to do powers in a for loop, such as raising (x+1) to a power of n, thanks for any help you guys can give...

 

[Zyrenthian]

well, you need to be aware that you can only do so much with an unsigned long/int. They only have 32 bits. You will either need to design a new class to handle LARGE numbers or give yourself a little more space with __int64.

however a for loop is not the quickest way to computer powers

remember that xⁿ can be computed as

value = x * x^(n-1)

Knowing this we can also apply another rule

if(n%2 == 0) // power divisable by 2
{
value = x^(n/2) * x^(n/2);
}


This should get you started with fast computations of powers

to do it in a for loop you will just loop "power" times and set value = x*value remembering to initialize value to 1


Matt

 

[aznrurouni]

was wondering how you use the parentheses for the power function, without using the ^ operator, however, i needed the forloop for an accumulation interest function...thanks for your reply...it works that way and if you use a #include <iomanip.h> also the pow (x,n) works, although kinda primative...i actually changed the int to a double for the decimal money values...thanks again