Errors with array

I am trying to run a C source code about Evolutionary Programming.
I get these errors after the compilation.
Anyone can help me to fix it? I am using VC 2005.
I need help urgently.


Here is the error part:--

Code:

---

double function14(int n)
{
double value;
int i,j;

double sum1,sum2,prod;

double a[n][25];

for(j=0;j<25;j=j+5)
{
a[0][j]=-32.0;
a[0][j+1]=-16.0;
a[0][j+2]=0.0;
a[0][j+3]=16.0;
a[0][j+4]=32.0;
}

---

error C2057: expected constant expression
error C2466: cannot allocate an array of constant size 0
error C2133: 'a' : unknown size


Thanks everyone

Code:

---

double a[n][25];

---

You can't use a variable as an array size when you declare an array. (except in C99 which most compilers don't support yet).

Quote:

---

Originally Posted by cpjust

Code:

---

double a[n][25];

---

You can't use a variable as an array size when you declare an array. (except in C99 which most compilers don't support yet).

---

Thanks for your quick response.
Actually i downloaded this program from internet.
I am trying to run it in my pc for studying about the Evolutionary Programming.

So i need to run it without changing the functions of this program.

Do you have any suggestion for me to make it run in my pc?

Thanks a lot.

Use malloc to dynamically create this array.

You could initialize a[n][25] with a constant value for n that is bigger than you would expect to see (I don't know what the function is for so I can't suggest one). You can use n everywhere else, though.

Or, to save space, you can make a[n] (where n is a large number) and have each index be a pointer to an array b[25].

i.e.,

Code:

---

double *a[255]
double b[25]
a[0]=b

---

I think this will work, correct me if I'm wrong.

Code:

---

double function19(int n)
{
  double value;
  int i,j;
  double sum1,sum2;
  double a[4][n],p[4][n];
  double c[4];
 

 

/* assign the values of left and right boundary  */
  for(i=0;i<n;i++)
  {
    left_bound[i]=0;
    right_bound[i]=1;
  }


   
    a[0][0]=3.0;
    a[0][1]=10.0;
    a[0][2]=30.0;

    a[1][0]=0.1;
    a[1][1]=10.0;
    a[1][2]=35.0;

    a[2][0]=3.0;
    a[2][1]=10.0;
    a[2][2]=30.0;

    a[3][0]=0.1;
    a[3][1]=10.0;
    a[3][2]=35.0;

    c[0]=1;
    c[1]=1.2;
    c[2]=3;
    c[3]=3.2;

    p[0][0]=0.3689;
    p[0][1]=0.1170;
    p[0][2]=0.2673;

    p[1][0]=0.4699;
    p[1][1]=0.4387;
    p[1][2]=0.7470;

    p[2][0]=0.1091;
    p[2][1]=0.8732;
    p[2][2]=0.5547;

    p[3][0]=0.038150;
    p[3][1]=0.5743;
    p[3][2]=0.8828;
 
 sum1=0.0;
 
 for(i=0;i<4;i++)
 {
  sum2=0.0;
 
  for(j=0;j<n;j++)
  {
    sum2=sum2+a[i][j]*pow(z[j]-p[i][j],2.0);
  }
  sum1=sum1+c[i]*exp(-sum2);
 }
 value=-sum1;
 return value;
}

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I am having the same errors for this part.
So sorry for the silly questions, i'm a beginner in C programming.

Quote:

---

Originally Posted by wingster

I am having the same errors for this part.
So sorry for the silly questions, i'm a beginner in C programming.

---

And the reason is the same:

Code:

---

double function19(int n)
{
  double value;
  int i,j;
  double sum1,sum2;
  double a[4][n],p[4][n];
  double c[4];

---

[edit]I don't see a declaration for the z array, is it a global? Plus, even if the array part worked, it would assume that n was always at least 3 (would that be checked in the calling func?).[/edit]

Thanks again to everyone.
Now i am facing another errors in my program.

Code:

---

void initilization(int n)
{
  int i,j;
  double segment;
 
  unsigned int start_time;

  time_t time1;

  (void) time(&time1);
  start_time=(int)time1;
  srand(start_time);

  for(j=0;j<max_n;j++)
  {
    z[j]=0.0;
  }

  for(i=0;i<population_size;i++)
  {
    individual_f[i]=function1(n);
  }

/* assign the initial values of points */

  for(i=0;i<population_size;i++)
  {
    for(j=0;j<n;j++)
    {
      individual_x[i][j]=left_bound[j]+rand()%10*0.1*(right_bound[j]-left_bound[j]);
      new_individual_x[i][j]=individual_x[i][j];
    }
  }

/* compute their fitness */
  for(i=0;i<population_size;i++)
  {
    for(j=0;j<n;j++)
    {
      z[j]=individual_x[i][j];
    }
    individual_f[i]=function(n);
    new_individual_f[i]=individual_f[i];
    //  printf("\n fitness[%d]=%10.5f",i,individual_f[i]);
  }

  /* assign the initial values of sigmas */
 

 
  for(i=0;i<population_size;i++)
  {
   
    for(j=0;j<n;j++)
    {
      individual_sigma[i][j]=3.0;//sqrt(0.1*(right_bound[j]-left_bound[j]));
      new_individual_sigma[i][j]=individual_sigma[i][j];
    }
  }

/* assign the initial values of mixed distribution */
  for(i=0;i<population_size;i++)
  {
    individual_mp[i]=rand()%no_strategy;
    new_individual_mp[i]=individual_mp[i];

  }
  for(i=0;i<no_strategy;i++)
  {
    for(j=0;j<no_strategy;j++)
    {
        p_history[i][j]=1.0/(double)no_strategy;
    }
  }
  /* assign the performance of each strategy a non-zero tiny positive */
  for(i=0;i<no_strategy;i++)
  {
    performance_of_best_mp[i]= 1.0e-10;
  }
}

---

error LNK2019: unresolved external symbol _function referenced in function _initilization
fatal error LNK1120: 1 unresolved externals

How can i fix this error?

Within your function initilization() you are doing this.

Quote:

---

Originally Posted by wingster

Code:

---

void initilization(int n)
{
  /*  Some stuff removed as not relevant to the error message */


/* compute their fitness */
  for(i=0;i<population_size;i++)
  {
    for(j=0;j<n;j++)
    {
      z[j]=individual_x[i][j];
    }
    individual_f[i]=function(n);
    new_individual_f[i]=individual_f[i];
    //  printf("\n fitness[%d]=%10.5f",i,individual_f[i]);
  }

  /*  Other stuff removed as not relevant to the error message */
}

---

---

and then you get

Quote:

---

Originally Posted by wingster

error LNK2019: unresolved external symbol _function referenced in function _initilization
fatal error LNK1120: 1 unresolved externals

---

"unresolved external symbol XXXX" is the way the linker tells you it tried to find something named XXXX and couldn't find it.

In this case, the reason is that you have not implemented function() anywhere.

The fix is either to remove the call of function from the line I've highlighted in red, or to actually provide an implementation of function().

It would help in future if you try to interpret the error messages rather than just giving up and asking for someone else to tell you what's wrong. Error messages from compilers and linkers may be a little geeky, but they are usually self-explanatory if you think things through.

The function have implemented here

Code:

---

double function1(int n)
{
  double value;
  int i,j;

/* assign the values of left and right boundary  */
  for(j=0;j<n;j++)
  {
    left_bound[j]=-100.0;
    right_bound[j]=100.0;
  }
  value =0.0;
  for(j=0;j<n;j++)
  {
    value=z[j]*z[j]+value;
  }
  return value;
}


/* function  9 (5 in Lee)*/
double function9(int n)
{
  double value;
  int i,j;



/* assign the values of left and right boundary  */
  for(j=0;j<n;j++)
  {
    left_bound[j]=-5.12;
    right_bound[j]=5.12;
  }

  value =0.0;
  for(i=0;i<n;i++)
  {
    value=z[i]*z[i]-10.0*cos(2*M_PI*z[i])+10.0+value;
  }
  return value;
}

---

but still not working. Thanks for your comments.

What errors are you getting now?

Quote:

---

Originally Posted by BEN10

What errors are you getting now?

---

The error is this:
error LNK2019: unresolved external symbol _function referenced in function _initilization
fatal error LNK1120: 1 unresolved externals

It seems you have function1 and function9 defined, but I don't function. You need to define function without any numbers, or you have a typo in your code

Code:

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    individual_f[i]=function(n);

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