pow

The following C code int main(){ int n=10; int t1=pow(10,2); int t2=pow(n,2); int t3=2*pow(n,2); printf("%d\n",t1); printf("%d\n",t2); printf("%d\n",t3); return (0); } gives the following output 100 99 199 I am using a devcpp compiler. It does not make any sense, right? Any ideas? (That pow(10,2) is maybe something like 99.9999 does not explain the first output. Moreover, I got the same output even if I include math.h) You are using a poor-quality math library. A good math library returns exact results for values that are exactly representable. Generally, math library routines must be

Anyone knows if multiply operator is faster than using the Math.Pow method? Like: n * n * n vs Math.Pow ( n, 3 ) Basically, you should benchmark to see. Educated Guesswork (unreliable): In case it's not optimized to the same thing by some compiler... It's very likely that x * x * x is faster than Math.Pow(x, 3) as Math.Pow has to deal with the problem in its general case, dealing with fractional powers and other issues, while x * x * x would just take a couple multiply instructions, so it's very likely to be faster. ggf31416 I just reinstalled windows so visual studio is not installed and the

This question already has an answer here: Strange behaviour of the pow function 5 answers I was simply writing a program to calculate the power of an integer. But the output was not as expected. It worked for all the integer numbers except for the power of 5. My code is: #include <stdio.h> #include <math.h> int main(void) { int a,b; printf("Enter the number."); scanf("\n%d",&a); b=pow(a,2); printf("\n%d",b); } The output is something like this: "Enter the number. 2 4 "Enter the number. 5 24 "Enter the number. 4 16 "Enter the number. 10 99 Can't we use pow() function for int data type??

I have some problems using an integer cast for the pow() function in the C programming language. The compiler I'm using is the Tiny C Compiler (tcc version 0.9.24) for the Windows platform. When executing the following code, it outputs the unexpected result 100, 99 : #include <stdio.h> #include <math.h> int main(void) { printf("%d, ", (int) pow(10, 2)); printf("%d", (int) pow(10, 2)); return 0; } However, at this online compiler the output is as expected: 100, 100 . I don't know what is causing this behavior. Any thoughts? Programming error from me, compiler bug? You found a bug in tcc. Thanks

If you try to run the following code public class Main { public static void main(String[] args) { long a = (long)Math.pow(13, 15); System.out.println(a + " " + a%13); } } You will get "51185893014090752 8" The correct value of 13^15 is 51185893014090757 , i.e. greater than the result returned by Math.pow by 5 . Any ideas of what may cause it? You've exceeded the number of significant digits available (~15 to 16) in double-precision floating-point values. Once you do that, you can't expect the least significant digit(s) of your result to actually be meaningful/precise. If you need arbitrarily