getting 'nan' error when code was working fine before (no compile error)

[Namster]

I do not know specifically where the error is so I apologise for posting the whole code in this post.

About one month after starting to learn c++ i decided to make a genetic algorithm for curve fitting a set on points. It was working perfectly fine and as shown in this picture the mean difference of points from their function is show clearly.
(screenshot)https://gyazo.com/25332cf70258788b9cc0189b31533b17

then after declaring another integer i get this error
(screenshot)https://gyazo.com/d568320011532e20804ffdfa4cfcae7f

i am sure this is the reason because it will work fine and then when i put declare this new variable at any line in the code and i will get the same error. it can be called anything and contain any value so here i am thinking that i have reached some sort of 'cap'.

can anyone help me out?

useful info (maybe):
Windows 7
CodeBlocks
No compile error

#include <iostream>
#include <cmath>
#include <ctime>
#include <cstdlib>

using namespace std;

int NumberOfPoints= 5;
int NumberOfFunctions = 6;
int PolynomialDegree = 2;

float RNG()
{
    float x;
    do{
        x = rand()%1000;
    }while( x < 100);
    x = x/100;
    return x;
}
class Function{
public:
void SetFunction2()
{
    a =  RNG();
    b =  RNG();
    c =  RNG();
    int RandomSign = rand()%2;
    if(RandomSign==1)
        a = -a;

    RandomSign = rand()%2;
    if(RandomSign==1)
        b = -b;

    RandomSign = rand()%2;
    if(RandomSign==1)
        c = -c;
}
void PrintFunction()
{
    cout << a <<"x^2 +" <<b <<"x + " << c;
}
float OutputDegree2(float InputFloat)
{
    return (a*pow(InputFloat,2) + b*InputFloat + c);
}
void SetMeanDifference(float x)
{
    MeanDiffence = x;
}
float GetMeanDifference()
{
    return MeanDiffence;
}
void SetScore(float InputTotalScore)
{
    DifferenceFromTotalf = InputTotalScore - GetMeanDifference();
    Score = round(DifferenceFromTotalf);
}
int GetScore()
{
    return Score;
}
void SetNormalisedScore(int LowestScore)
{
    NormalisedScore = GetScore() - LowestScore;
    if(NormalisedScore == 0)
    {
        NormalisedScore = 1;
    }
}
int GetNormalisedScore()
{
    return NormalisedScore;
}

private:
    float a;
    float b;
    float c;

    float MeanDiffence;
    float DifferenceFromTotalf;
    int Score;
    int NormalisedScore;
};


int main()
{
    /// set points
float Points[NumberOfPoints][2];
    Points[0][0] = -6.24;   Points[0][1] = 3.41;
    Points[1][0] = 3.49;    Points[1][1] = 6.90;
    Points[2][0] = 2.24;    Points[2][1] = 1.62;
    Points[2][0] = 10.24;    Points[2][1] = -7.63;

    srand(time(0));
Function Parents[NumberOfFunctions]; ///create functions
for (int i =0; i<NumberOfFunctions ;i++)
{
    Parents[i].SetFunction2();
}
///print functions
for(int i = 0 ; i<NumberOfFunctions;i++)
{
    Parents[i].PrintFunction();
    cout << endl;
}
///calculate mean difference of each point of each function
for(int x =0;x < NumberOfFunctions;x++){

    float TotalDifference = 0;
    for(int i = 0; i < NumberOfPoints;i++)
    {
    TotalDifference = TotalDifference + abs(Parents[x].OutputDegree2(Points[i][0]) - Points[i][1]);
    }

    float MeanDifference = TotalDifference/NumberOfPoints;
    Parents[x].SetMeanDifference(MeanDifference);
}
cout <<"average mean differences:\n" ;
for(int i =0; i <NumberOfFunctions;i++)
{
    cout << Parents[i].GetMeanDifference() << endl;
}

///set scores
float TotalDifferencef = 0 ;

for(int i = 0 ; i < NumberOfFunctions;i++)
{
  TotalDifferencef = TotalDifferencef + Parents[i].GetMeanDifference();
}
cout << "\nTotalDifference :" <<TotalDifferencef << endl;

for(int i=0;i <NumberOfFunctions;i++)
{
    Parents[i].SetScore(TotalDifferencef);
}
cout << "\nDifferences from Total\n";

for(int i=0;i<NumberOfFunctions;i++)
{
    cout << Parents[i].GetScore();
    cout << endl;
}
int LowestScore = Parents[0].GetScore();
///get normalised score
for(int i=0;i<NumberOfFunctions;i++)
{
    if(Parents[i].GetScore() < LowestScore)
    LowestScore = Parents[i].GetScore();
}
cout << "\nLowestScore:" << LowestScore << endl;


int TotalNormalisedScore = 0;
for(int i=0;i<NumberOfFunctions;i++)
{
    Parents[i].SetNormalisedScore(LowestScore);
    cout << Parents[i].GetNormalisedScore() <<endl;
    TotalNormalisedScore = TotalNormalisedScore + Parents[i].GetNormalisedScore();
}

int RandomParentSelector = rand()%TotalNormalisedScore +1;

cout << "TotalNormalisedScore: " << TotalNormalisedScore <<endl;
cout << "RandomNumber: " << RandomParentSelector << endl;

int newtestinteger = 5;



return 0;
}

[jlb]

Although your code seems to compile without errors, it does seem to have some warnings:

main.cpp||In function ‘int main()’:|
main.cpp|93|warning: variable length array ‘Points’ is used [-Wvla]|
main.cpp|99|warning: zero as null pointer constant [-Wzero-as-null-pointer-constant]|
main.cpp|100|warning: variable length array ‘Parents’ is used [-Wvla]|
main.cpp|172|warning: unused variable ‘newtestinteger’ [-Wunused-variable]|

VLA (Variable Length Arrays) are not valid standard C++ and should not be used. Arrays in C++ should be compile times constants. The following:

using namespace std;

int NumberOfPoints= 5;
int NumberOfFunctions = 6;
int PolynomialDegree = 2;

Should probably be const qualified values, this should solve the VLA issues, since these variables seem to be used to size the arrays.

And really you should consider using std::vector instead of the arrays.