calculating 2^601 results in "1.#INF00"

[Alexandre Proulx]

I am trying to find 2 at the power of 601, but my calculator doesn't have a large enough screen, so I decided to make a program for my computer to do this, but when I get to a high number the computer only prints : 1.#INF00. Is there any way to do it? My code is the fallowing:

 #include <iostream> 
#include <stdio.h>
#include <math.h>
 
using namespace std;
float a;
float x;
float y;
 
main()
{
x=2;
y=601;
a = pow(x,y);
printf("%f",a);
cin.get();
} 
 

[DeMan]

I must admit I've not actually used the library, so I'm not sure how it would be used, but I will look into it if I get a chance.

[DeMan]

here are some examples that may help you:

Large Floating point numbers:

#include <NTL/RR.h>
 
int main()
{
   RR acc, val; //use RR to declare big floats
 
   acc = 0;
   while (SkipWhiteSpace(cin)) {
      cin >> val;
      acc += val*val;  //use c in and cout rather than prinf
   }
 
   cout << acc << "\n";
}
 
 

Large integers:

#include <NTL/ZZ.h>
 
NTL_CLIENT
 
int main()
{
   ZZ a, b, c;  //use ZZ to declare ints
 
   cin >> a; 
   cin >> b; 
   c = (a+1)*(b+1);
   cout << c << "\n";  //use cin cout to use input and output with these types
}
 
 

[Alexandre Proulx]

Thanks it works! And by the way does anybody know how to display large numbers without scientific notations?

 #include <iostream> 
#include <math.h>
 
#include <NTL/RR.h>
 
#define NTL_NO_MIN_MAX
 
using namespace std;
NTL_CLIENT
 
 
int main()
{
RR a, x, y;
 
 
x=2;
y=33;
a = pow(x,y);
cout<<a<< "\n";
cin.get();
}
 

[ahammad]

You can use the manipulators in the iomanip header file. Also read up on the printf formats...they can be programmed to display a certain precision.

Also, for future reference, there is a 64 bit int that can be defined in C++. I think it's something like:

__int64

[Alexandre Proulx]

How would that go in my program? My Program is on the reply just before your's.

[ahammad]

It's been a while since I used them, and I don't have time right now to do it for you.

Here is a link to my old class notes for C++

http://www.sce.carleton.ca/courses/e...hapter%204.pdf

Jump to pages 16-20 for the output manipulators. The professor that wrote these is excellent and makes everything very simple.

[DeMan]

A 64 bit int gives you 2^64 values....

[hagelbc]

float is too small for the result of 2^602 try this
replace

float a;
float x;
float y;

for

double a;
double x;
double y;

or

long double a;
long double x;
long double y;

[DeMan]

which is why the NTL (Number Theory Library) was introduced earlier in this thread

[Alexandre Proulx]

It's been a while since I used them, and I don't have time right now to do it for you.

Here is a link to my old class notes for C++

http://www.sce.carleton.ca/courses/e...hapter%204.pdf

Jump to pages 16-20 for the output manipulators. The professor that wrote these is excellent and makes everything very simple.

Thanks for your texts, it works but not with NTL, since with the setiosflags(ios ::fixed) function only type double is accepted.
Does anybody know of a way that is compatible with NTL?