C++ power function help!

chris85

Hi i am a novice user to c++ program. I have an equation that i need to raise to the power of -2. How do I write this? I have tried writing as follows:

x=POWER(equation, (p))

where p is the power i want to raise the equation to.

This does not seem to be working. I am getting an error that the POWER identifier is not found. I tried defining POWER as a float but this did not work either. The program itself does work, i know that much. :rolleyes:

Any body got any help? i am a novice user so dont know too much about this and I know it is a simple fix but can get it

Naikon

Just use the inbuilt pow C function or use a for loop.
The syntax in C has to follow something similar to this:

power = pow( x , y );

Where pow returns say x as above to the power y and stores the value
in the variable named power. Declare the variables as double int's though to reduce the risk
of overflow.
EDIT, I see you are raising to a negetive power.

chris85

Naikon wrote: »

Just use the inbuilt pow C function or use a for loop.
The syntax in C has to follow something similar to this:

power = pow( x , y );

Where pow returns say x as above to the power y and stores the value
in the variable named power. Declare the variables as double int's though to reduce the risk
of overflow.
EDIT, I see you are raising to a negetive power.

Ok hows this look,

POWER=pow((2*log(Re*sqrt(f_old))-0.8), -2);
f_new=POWER;

seems to work ok in the program.

Naikon

chris85 wrote: »

Ok hows this look,

POWER=pow((2*log(Re*sqrt(f_old))-0.8), -2);
f_new=POWER;

seems to work ok in the program.

It works:)