Program Euler dan grafik C++

*> Program Euler

#include <iostream.h> 
#include <stdlib.h> 
#include <coni0.h> 
#include <stdi0.h> 
#include <mah.h> 
 
#define MaksData 100 
 
main() 
{ 
 FILE *euler; 
    double  x[MaksData], y[MaksData], 
             dx, dy[MaksData], 
             xn, x0, xtemp, 
             y0, ytemp; 
   int i, n; 
    char lagi; 
 
    do 
    { 
     clrscr(); 
     euler = fopen("euler.txt", "w+"); 
 
     cout << "\n\nMetode Euler untuk Diferensiasi Numerik\n"; 
     cout << "=======================================\n\n";
       cout << "Persamaan Diferensial : f(x,y) = dy/dx = (y - x)/(y + x)\n"; 
       cout << "--------------------------------------------------------\n\n"; 
 
             /* Pemasukan Data yang diberikan */ 
     cout << "\nMasukkan x[0] ? "; 
       cin >> x0;
       cout << "\nMasukkan y[0] ? "; 
     cin >> y0; 
       cout << "\nNilai x yang dicari ? "; 
     cin >> xn; 
       cout << "\nBerapa kali Iterasi ? "; 
     cin >> n; 
 
       dx = (xn - x0)/n; 
 
       printf("\n\n\tx[0] = %.2f", x0); 
       printf("\n\n\ty[0] = %.2f", y0); 
       printf("\n\n\tYang dicari adalah y[%.2f]", xn); 
       printf("\n\n\th = %.2f", dx); 
     printf("\n\n\tIterasi (n) = %d  kali", n); 
 
     /* Cetak x[i], y[i], dx[i] dan dy[i] serta penghitungan Euler */ 
     printf("\n\n\t-------------------------------------------------------\n"); 
     printf("\tIterasi\t\tx[i]\tdy[i]\t\tdx[i]\ty[i]\n"); 
     printf("\t-------------------------------------------------------\n"); 
     fprintf(euler,"\n\t-------------------------------------------------------\n");
     fprintf(euler,"\tIterasi\t\tx[i]\tdy[i]\t\tdx[i]\ty[i]\n"); 
     fprintf(euler,"\t-------------------------------------------------------\n");
 
     /* Pemasukan dan Penghitungan Data */ 
     for(i = 1; i <= n; i++) 
     { 
           /* Rumus Diferensiasi Euler */ 
           dy[i] = ((y0 - x0)/(y0 + x0)) * dx; 
           y[i] = y0 + dy[i]; 
           x[i] = x0 + dx; 
  
 
 
        printf("\t   %d\t\t%.2f\t%.5f\t\t%.2f\t%.5f\n", i, x[i-1], dy[i], dx,  
   y[i]); 
        fprintf(euler,"\t   %d\t\t%.2f\t%.5f\t\t%.2f\t%.5f\n", i, x[i-1],  
   dy[i], dx, y[i]); 
 
           ytemp = y[i]; 
           y0 = ytemp; 
 
           xtemp = x[i]; 
           x0 = xtemp; 
       }
 
     printf("\t-------------------------------------------------------\n"); 
     fprintf(euler,"\t-------------------------------------------------------\n");
       fprintf(euler,"\n\nx[%d] = %.2f", i-n-1, x[i-n-1]); 
       fprintf(euler,"\n\nYang dicari adalah y[%.2f]", xn); 
     fprintf(euler,"\n\nh = %.2f", dx); 
       fprintf(euler,"\n\nIterasi (n) = %d  kali", n); 
     printf("\n\nMaka y[%.2f] = %.5f", xn, y0); 
     fprintf(euler,"\n\nMaka y[%.2f] = %.5f", xn, y0); 
     fclose(euler); 
 
       cout << "\n\nCoba lagi dengan data awal atau rumus yang berbeda (y/t) ? "; 
       cin >> lagi; 
 
    }while(lagi != 't'); 
 
   return 0; 
} 

*> Program grafik metode numerik

#include <iostream.h> 
#include <stdlib.h> 
#include <conio.h> 
#include <stdio.h> 
#include <math.h> 
 
main() 
{ 
   FILE *stream; 
   int i, j; 
   double x, dx, y1, y2, dy; 
 
   clrscr(); 
   stream = fopen("grafik.txt", "w+"); 
 
   cout << "Metode Grafik\n"; 
   cout << "-------------\n\n"; 
 
   cout << "Maksimum Iterasi = "; 
   cin >>j; 
   cout<< "Berapa Nilai Awal x = "; 
   cin >> x; 
   cout<< "Berapa Nilai Interval x = "; 
   cin >> dx; 
 
   //persamaan awal x^4 - 3x - 2 
   //y1 = x^4, y2 = 3x + 2 
 
   printf("\n\t------------------------------------------------\n"); 
   printf("\tIterasi ke-\tx\ty1\ty2\tSelisih\n"); 
   printf("\t------------------------------------------------\n\n"); 
   fprintf(stream, "\n\t------------------------------------------------\n"); 
   fprintf(stream, "\tIterasi ke-\tx\ty1\ty2\tSelisih\n"); 
   fprintf(stream, "\t------------------------------------------------\n\n"); 
 
   for(i = 0; i < j; i++) 
   {   
     y1 = pow(x,4); 
     y2 = 3*x + 2; 
     dy = y1 - y2; 
 
     printf("\t\t%d\t%.2f\t%.2f\t%.2f\t%.2f\n", i+1, x, y1, y2, dy); 
     fprintf(stream,"\t\t%d\t%.2f\t%.2f\t%.2f\t%.2f\n", i+1, x, y1, y2, dy); 
 
     x += dx; 
   } 
 
 
    printf("\t------------------------------------------------\n\n"); 
   fprintf(stream, "\t------------------------------------------------\n\n"); 
    
   fclose(stream); 
   getch(); 
   return 0; 
} 

silahkan copas dan edit sendiri...