Using functions

Lab#4

//декларация библиотек
#include <vcl.h>      // Visual Component Library
#include <stdio.h>    // standard input/output header
#include <conio.h>    //console input-output
#include <math.h>     //mathematics
#include <stdlib.h>   //standard library
#include <alloc.h>    //work with dynamic memory
#pragma hdrstop       //
#pragma argsused      //


typedef double (*Ufun)(double); 
double  fun1(double);
double  fun2(double);

double Out_Rez (Ufun,double);    
//îñíîâà
int n;

void main()
{
        double a,b,x,h,result_funct1,result_funct2;
        int i,sign;
        do{
                clrscr();
                fflush(stdin);
                printf(" 1 - Example, others digits -your's inp\n");
                scanf("%d",&sign);
                if (sign==1) {
                        a=0.1; b=1.0; h=0.1;
                        n=10;
                }
                else {
                        n=b/h;
                        n++;
                        do {
                                printf( "print a,b,h\n" );
                                fflush( stdin );
                        } while(scanf( "%lf%lf%lf",&a,&b,&h) !=3 );
                }
                printf("\n          First function   Second function    F1(x)- F2(x)|\n           ");
                for( double x=a; x<=b; x+=h )
                {
                        result_funct1=Out_Rez ( fun1,x );
                        result_funct2=Out_Rez ( fun2,x );
                        printf( "\nx=%2.2lf      %lf        %lf         %lf\n",x,result_funct1,
                                                result_funct1,fabs( result_funct1-result_funct2 ) );
                }

                puts("\nExit - 1, Restart - any key");
        } while ( getch() != '1');
}

double  fun1( double x){
        int k,sup;
        double r,s;

                        r=1;
                        s=0;
                        for ( k=1; k<=n; k++ )  {
                                r=-r*4*x*x/( ( 2*k-1 )*2*k );
                                s+=r;

                        }


        return s;
}
double fun2 ( double x ) {
        return 2*( cos( x )*cos( x )-1 );
}
double Out_Rez ( Ufun f ,double x ) {
      return f(x);
}

//---------------------------------------------------------------------------