# D code optimization

```It is often being claimed that D is at least as fast as C++.
```
Now, I am fairly new to D. But, here is an example where I want to see how can this be made possible.

```
So far my C++ code compiles in ~850 ms.
While my D code runs in about 2.1 seconds.

```
The code translated in D looks as follows (can't see any attach button here):
```
import std.stdio, std.math;
import std.datetime;

int main() {

StopWatch sw;
sw.start();

double C=0.0;

for (int k=0;k<10000;++k) { // iterate 1000x

double S0 = 100.0;
double r = 0.03;
double alpha = 0.07;
double sigma = 0.2;
double T = 1.0;
double strike = 100.0;
double S = 0.0;

const int n = 252;

double dt = T / n;
double R = exp(r*dt);

double u = exp(alpha*dt + sigma*sqrt(dt));
double d = exp(alpha*dt - sigma*sqrt(dt));

double qU = (R - d) / (R*(u - d));
double qD = (1 - R*qU) / R;

//double* call = new double [n + 1];
double[] call = new double[n+1];

```
for (int i = 0; i <= n; ++i) call[i] = fmax(S0*pow(u, n-i)*pow(d, i)-strike, 0.0);
```
for (int i = n-1; i >= 0 ; --i) {
for (int j = 0; j <= i; ++j) {
call[j] = qU * call[j] + qD * call[j+1];
}
}

C = call[0];

```
//delete call; // since D is has a garbage collector, explicit deallocation of arrays is not necessary.
```            // nevertheless we do this
}

long exec_ms = sw.peek().msecs;

```
writeln("Option value: ", C, " / execution time: ", exec_ms, " ms\n" );
```
return 0;
}
```