Help with my code please

[jtcorlett]

here is what I have so far, and I know there are a lot of errors I just need some help please.

#include <iostream>
#include <cmath>
#include <algorithm>
#include <functional>
#include <string>
using namespace std;

const double ARM1_LENGTH=.87f;
const double ARM2_LENGTH=.59f;
double CurrentPosition[3] = [theta1, theta2, theta3];
//double Destination[3] = [1,1,1]; // also for compiling
//int CurrentPosition[3]=[0,0,0]; // for input data to compile
double P[3] = CurrentPosition[3], BMNewThetas[3];

int main() 
{
BMlastD = Distance(CurrentPosition[3], Destination[3]); // testing
BMNewThetas[3] = BM(P[3]); // testing
BMNewD = Distance (BMNewThetas[3]); //  testing

  while (BMlastD != BMNewD)
  {
    BMlastD = BMNewD;
    BMNewThetas[3] = BM(BMNewThetas[3]);
    BMNewD = Distance(forwardkinematics(BMNewThetas[3]), Destination[3]);
  } 

return (BMNewThetas[3])
}
{
double forwardkinematics (double T[3])

  x = cos(T[0])*(ARM1_LENGTH*(cos(T[1]))+(ARM2_LENGTH)*cos(T[1]+T[2]));
  y = sin(T[0])*(ARM1_LENGTH*(cos(T[1]))+(ARM2_LENGTH)*cos(T[1]+T[2]));
  z = (ARM1_LENGTH)*sin(T[1])+ARM2_LENGTH(sin(T[1]+T[2]));
  return([x,y,z]);
}

double distance (double A[3],double B[3])
{
  return sqrt((B[2]-A[2])*(B[2]-A[2])+(B[1]-A[1])*(B[1]-A[1])+(B[0]-A[0])*(B[0]-A[0]));
}
{
double BM(double T[3])
}
{
double theta1=T[0], theta2=T[1], theta3=T[2];
P[3] = forwardkinematics(T[3]);
shortestdistance = distance (P[3]);
int besti, bestj, bestk;
for(int i = -1; i<2; i++)
{
  for(int j = -1; j<2; j++)
  {
    for(int k = -1; k<2; k++)
    { 
      P[3] = forwardkinematics([theta1+i, theta2+j, theta3+k]);
      if (distance(P) < shortestdistance)
      {
         besti = i; bestj = j; bestk = k;
      }
    }
  }
}
return ([theta1+besti, theta2+bestj, theta3+bestk]);
}
[code]

[/code]

[TheIdeasMan]

Firstly, please edit your post so it uses code tags - the <> button on the right. You might get more replies if you always do this. If you have compile errors, then post these in full as well.

2 things that stand out are the non-declaration of your variables, and the cases sensitiveness of variable / function names.

HTH

Edit: Also, make sure to have some decent indenting in your code as well.

[jtcorlett]

Here is the compiling errors I get, and can you help me with the non-declaration, this is my first c++ project.

Thank you


anonymous@anonymous-Linux ~/Desktop/Arm Code $ gcc acn.cpp
acn.cpp:10:30: error: ‘theta1’ was not declared in this scope
acn.cpp:10:38: error: ‘theta2’ was not declared in this scope
acn.cpp:10:46: error: ‘theta3’ was not declared in this scope
acn.cpp:10:52: error: type ‘<lambda>’ with no linkage used to declare function ‘void<lambda>::operator()() const’ with linkage [-fpermissive]
acn.cpp: In lambda function:
acn.cpp:10:53: error: expected ‘{’ before ‘;’ token
acn.cpp: At global scope:
acn.cpp:10:53: warning: lambda expressions only available with -std=c++0x or -std=gnu++0x [enabled by default]
acn.cpp:13:32: error: array must be initialized with a brace-enclosed initializer
acn.cpp: In function ‘int main()’:
acn.cpp:17:1: error: ‘BMlastD’ was not declared in this scope
acn.cpp:17:40: error: ‘Destination’ was not declared in this scope
acn.cpp:17:54: error: ‘Distance’ was not declared in this scope
acn.cpp:18:25: error: ‘BM’ was not declared in this scope
acn.cpp:19:1: error: ‘BMNewD’ was not declared in this scope
acn.cpp:23:15: error: ‘BMNew’ was not declared in this scope
acn.cpp:25:55: error: ‘forwardkinematics’ was not declared in this scope
acn.cpp:29:1: error: expected ‘;’ before ‘}’ token
acn.cpp: At global scope:
acn.cpp:30:1: error: expected unqualified-id before ‘{’ token
acn.cpp:43:1: error: expected unqualified-id before ‘{’ token
acn.cpp:46:1: error: expected unqualified-id before ‘{’ token

[hjone]

double CurrentPosition[3] = [theta1, theta2, theta3];
needs theta1, theta2, and theta3, variables that are declared inside function BM. When the function BM ends, the variable goes out of scope.

[jtcorlett]

The variables of theta1, theta2, and theta3. Will be given to me on the test day. They will change, how do I fix the other issues?

EDIT: Thank you so much for helping and sorry for all the questions, and noobish answers.

[TheIdeasMan]

acn.cpp:10:30: error: ‘theta1’ was not declared in this scope
acn.cpp:10:38: error: ‘theta2’ was not declared in this scope
acn.cpp:10:46: error: ‘theta3’ was not declared in this scope

This says that the variables on line 10 are not declared. You must declare variables with a type, and you also must initialise them, before you use them in an expression.

acn.cpp:10:52: error: type ‘<lambda>’ with no linkage used to declare function ‘void<lambda>::operator()() const’ with linkage [-fpermissive]
acn.cpp:10:53: error: expected ‘{’ before ‘;’ token
acn.cpp:10:53: error: expected ‘{’ before ‘;’ token

This one is due to the square brackets:
double CurrentPosition[3] = [theta1, theta2, theta3];

You should always use braces to initialise arrays:

double CurrentPosition[3] = {theta1, theta2, theta3};

acn.cpp:13:32: error: array must be initialized with a brace-enclosed initializer

Same thing here:
double P[3] = CurrentPosition[3], BMNewThetas[3];

Except that P[3] is an array of 3 doubles, you are trying to initialise it with two arrays that contain 3 items each - doesn't make sense.

This code:
BMlastD = Distance(CurrentPosition[3], Destination[3]); // testing

Produces these errors:

acn.cpp: In function ‘int main()’:
acn.cpp:17:1: error: ‘BMlastD’ was not declared in this scope
acn.cpp:17:40: error: ‘Destination’ was not declared in this scope
acn.cpp:17:54: error: ‘Distance’ was not declared in this scope

BMlastD is not declared.
Distance is a function call, but the function is named distance.


BMNewThetas[3] = BM(P[3]); // testing

You can't assign arrays like that.

acn.cpp:25:55: error: ‘forwardkinematics’ was not declared in this scope

This is because of the extra & mismatched braces further down, that the compiler doesn't recognise forwardkinematics as a function definition on lines 31 -37. With braces, if you are using an IDE - you can get it to do closing braces automatically.

Hope all goes well.

[TheIdeasMan]

for(int i = -1; i<2; i++)
{
  for(int j = -1; j<2; j++)
  {
    for(int k = -1; k<2; k++)
    { 
      P[3] = forwardkinematics([theta1+i, theta2+j, theta3+k]);
      if (distance(P) < shortestdistance)
      {
         besti = i; bestj = j; bestk = k;
      }
    }
  }
}

With this, arrays start at zero, so your for loops should as well. You have unnecessary braces.

for(int i = 0; i<3; i++)
  for(int j = 0; j<3; j++)
    for(int k = 0; k<3; k++) { 
      P[3] = forwardkinematics(theta1, theta2, theta3);
      if (distance(P) < shortestdistance) {
         besti = i; bestj = j; bestk = k;
      }
    }

I would use different variable names - i & j can get confusing. x, y , z would be OK in this case because they represent spatial coordinates. Otherwise you use East, North, Height as an example.

Now that I have rewritten it, the whole thing doesn't make sense.

[jtcorlett]

Thank You so much, this helps a LOT! You're a life saver. I fixed issues and it is working. Thank you! Thank you! Thank you!

[TheIdeasMan]

One final thing - Don't put multiple statements on one line.

Does your code produce the right answers?