Task: Mandelbrot set
C:  
 #include <stdio.h>
 #include <math.h>
 int main()
 {
          
        int iX,iY;
        const int iXmax = 800; 
        const int iYmax = 800;
        
        double Cx,Cy;
        const double CxMin=-2.5;
        const double CxMax=1.5;
        const double CyMin=-2.0;
        const double CyMax=2.0;
        
        double PixelWidth=(CxMax-CxMin)/iXmax;
        double PixelHeight=(CyMax-CyMin)/iYmax;
        
        
        const int MaxColorComponentValue=255; 
        FILE * fp;
        char *filename="new1.ppm";
        char *comment="# ";
        static unsigned char color[3];
        
        double Zx, Zy;
        double Zx2, Zy2; 
        
        int Iteration;
        const int IterationMax=200;
        
        const double EscapeRadius=2;
        double ER2=EscapeRadius*EscapeRadius;
        
        fp= fopen(filename,"wb"); 
        
        fprintf(fp,"P6\n %s\n %d\n %d\n %d\n",comment,iXmax,iYmax,MaxColorComponentValue);
        
        for(iY=0;iY<iYmax;iY++)
        {
             Cy=CyMin + iY*PixelHeight;
             if (fabs(Cy)< PixelHeight/2) Cy=0.0; 
             for(iX=0;iX<iXmax;iX++)
             {         
                        Cx=CxMin + iX*PixelWidth;
                        
                        Zx=0.0;
                        Zy=0.0;
                        Zx2=Zx*Zx;
                        Zy2=Zy*Zy;
                        
                        for (Iteration=0;Iteration<IterationMax && ((Zx2+Zy2)<ER2);Iteration++)
                        {
                            Zy=2*Zx*Zy + Cy;
                            Zx=Zx2-Zy2 +Cx;
                            Zx2=Zx*Zx;
                            Zy2=Zy*Zy;
                        };
                        
                        if (Iteration==IterationMax)
                        { 
                           color[0]=0;
                           color[1]=0;
                           color[2]=0;                           
                        }
                     else 
                        { 
                             color[0]=255; 
                             color[1]=255;   
                             color[2]=255;
                        };
                        
                        fwrite(color,1,3,fp);
                }
        }
        fclose(fp);
        return 0;
 }

C++: #include <cstdlib>
#include <complex>


template<typename ElementType, std::size_t dim1, std::size_t dim2>
 std::size_t get_first_dimension(ElementType (&a)[dim1][dim2])
{
  return dim1;
}

template<typename ElementType, std::size_t dim1, std::size_t dim2>
 std::size_t get_second_dimension(ElementType (&a)[dim1][dim2])
{
  return dim2;
}


template<typename ColorType, typename ImageType>
 void draw_Mandelbrot(ImageType& image,                                   
                      ColorType set_color, ColorType non_set_color,       
                      double cxmin, double cxmax, double cymin, double cymax,
                      unsigned int max_iterations)                          
{
  std::size_t const ixsize = get_first_dimension(image);
  std::size_t const iysize = get_first_dimension(image);
  for (std::size_t ix = 0; ix < ixsize; ++ix)
    for (std::size_t iy = 0; iy < iysize; ++iy)
    {
      std::complex<double> c(cxmin + ix/(ixsize-1.0)*(cxmax-cxmin), cymin + iy/(iysize-1.0)*(cymax-cymin));
      std::complex<double> z = 0;
      unsigned int iterations;

      for (iterations = 0; iterations < max_iterations && std::abs(z) < 2.0; ++iterations) 
        z = z*z + c;

      image[ix][iy] = (iterations == max_iterations) ? set_color : non_set_color;

    }
}