Difference between revisions of "C++:3D Exercises"

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(Normalise a vector)
(Normalise a vector)
Line 163: Line 163:
  
 
<prog><![CDATA[
 
<prog><![CDATA[
 +
#include <math.h>
 +
#include <iostream>
 +
using namespace std;
 +
 +
int main(int argc, char **argv)
 +
{
 +
  float A[]={1,0,1};
 +
  float B[]={1,1,2};
 +
  float *C;
 +
  cout << C[0]<<" "<<C[1]<<" "<<C[2]<< endl;
 +
  cout << C[0]<<" "<<C[1]<<" "<<C[2]<< endl;
 +
  return 0;
 +
}
 +
]]></prog>
 +
 +
<answer><![CDATA[
 
#include <math.h>
 
#include <math.h>
 
#include <iostream>
 
#include <iostream>
Line 168: Line 184:
  
 
float length(float a[3]){
 
float length(float a[3]){
   float r=0; // Your code goes here
+
   float r=sqrt(a[0]*a[0]+a[1]*a[1]+a[2]*a[2]);
 +
  return r;
 +
}
 +
 
 +
float *scalarproduct(float x,float a[3]){
 +
  float *r = new float[3];
 +
  for (int i=0;i<3;i++)
 +
    r[i] = x*a[i];
 
   return r;
 
   return r;
 
}
 
}
Line 176: Line 199:
 
   float A[]={1,0,1};
 
   float A[]={1,0,1};
 
   float B[]={1,1,2};
 
   float B[]={1,1,2};
   cout << length(A)<< endl;
+
   float *C = scalarproduct(1.0/length(A),A);
   cout << length(B)<< endl;
+
  cout << C[0]<<" "<<C[1]<<" "<<C[2]<< endl;
 +
   C = scalarproduct(1.0/length(B),B);
 +
  cout << C[0]<<" "<<C[1]<<" "<<C[2]<< endl;
 
   return 0;
 
   return 0;
 
}
 
}
]]></prog>
 
 
<answer><![CDATA[
 
 
]]></answer>
 
]]></answer>
 
</question>
 
</question>

Revision as of 08:36, 24 November 2011

Dot Product

Calculate the dot product of two vectors. Fill in the details in the function dotproduct

Wikipedia includes a good article on dot products. http://en.wikipedia.org/wiki/Dot_product#Definition



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Cross Product

Calculate the cross product of two vectors. Fill in the details in the function crossproduct

Wikipedia includes a good article on cross products. http://en.wikipedia.org/wiki/Cross_product#Coordinate_notation



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Vector Length

Calculate the magnitude of a vector. Fill in the details in the function length



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Normalise a vector

Normalise the given vector. The direction should be the same, the length should be 1.



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Normal to a plane

Find the unit normal to the plane that contains the three points given.



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