how to generate random numbers between two doubles in c++ , these number should look like xxxxx,yyyyy .
thanks
+4
A:
Here's how
double fRand(double fMin, double fMax)
{
double f = (double)rand() / RAND_MAX;
return fMin + f * (fMax - fMin);
}
Remember to call srand() with a proper seed each time your program starts.
rep_movsd
2010-04-24 13:10:34
to exclude max (often done): add +1 to RAND_MAX
KillianDS
2010-04-24 13:12:13
If you add 1 to RAND_MAX, do so carefully, since it might be equal to INT_MAX. `double f = rand() / (RAND_MAX + 1.0);`
Steve Jessop
2010-04-24 13:22:55
Note that the randomness of this can be limited. The range xxxxx,yyyyy suggests 10 decimal digits. There are plenty of systems where RAND_MAX is smaller than 10^10. This would mean that some numbers in that range have `p(xxxxx,yyyyy)==0.0`
MSalters
2010-04-26 12:46:46
A:
something like this:
#include <iostream>
#include <time.h>
using namespace std;
int main()
{
const long max_rand = 1000000L;
double x1 = 12.33, x2 = 34.123, x;
srandom(time(NULL));
x = x1 + ( x2 - x1) * (random() % max_rand) / max_rand;
cout << x1 << " <= " << x << " <= " << x2 << endl;
return 0;
}
oraz
2010-04-24 13:13:41