new Metode Newton Raphson - Tabel

#include <stdio.h>
#include <math.h>
#define maks 25
#define D 0.00001

double x[maks], x0[maks], x1, y[maks], xatas, xbawah, h, err, e;
int N, i, j, n=0;
FILE *file;

double fungsix (double x){
    return((x*exp(-x))+cos(2*x));
}

double diffungsix (double x){
    return(((1-x)*exp(-x))-2*sin(2*x));
}

void input(){
    printf("Masukkan batas atas\t: ");
    scanf("%lf", &xatas);
    printf("Masukkan batas bawah\t: ");
    scanf("%lf", &xbawah);
    printf("Masukkan jumlah pembagi\t: ");
    scanf("%d", &N);
    printf("Masukkan Toleransi Error: ");
    scanf("%lg", &e);
            fprintf(file,"Batas bawah\t: %lf\n",xatas);
            fprintf(file,"Batas atas\t: %lf\n",xbawah);
            fprintf(file,"Jumlah pembagi\t: %d\n",N);
            fprintf(file,"Toleransi Error\t: %lg\n",e);
    h=(xatas-xbawah)/N;
}

void tabel(){
    double akar;
    printf("\nHasilnya adalah :\n");
    printf("============================");
    printf("\n| %2s |  %-4s |    %-8s |\n", "i", "x[i]", "y[i]");
    printf("|====|=======|=============|\n");
        fprintf(file,"\nHasilnya adalah :\n");
        fprintf(file,"============================");
        fprintf(file,"\n| %2s |  %-4s |    %-8s |\n", "i", "x[i]", "y[i]");
        fprintf(file,"|====|=======|=============|\n");
    for(i=0; i<N; i++){
        x[i]=xbawah+i*h;
        y[i]=fungsix(x[i]);
        printf("| %2d | %-5lg | %-12lg|\n",i+1,x[i],y[i]);
            fprintf(file,"| %2d | %-5lg | %-12lg|\n",i+1,x[i],y[i]);
    }
    printf("============================\n\n");
        fprintf(file,"============================\n\n");
    for(j=0; j<N-1; j++){
        if(y[j]==0){
            printf("Akarnya adalah %lg\n", x[j]);
                fprintf(file,"Akarnya adalah %lg\n", x[j]);
            if(fabs(diffungsix(x0[n]))){
                x0[n]=x0[n]+D;
            }
        }
        else if(y[j]*y[j+1]<0){
            printf("Akar diantara %lg dan %lg\n", x[j],x[j+1]);
                fprintf(file,"Akar diantara %lg dan %lg\n", x[j],x[j+1]);
            if(fabs(y[j])<fabs(y[j+1])){
                printf("Akarnya : %lg\n", x[j]);
                    fprintf(file,"Akarnya : %lg\n", x[j]);
                x0[n]=x[j];
                n++;
            }
            else{
                printf("Akarnya : %lg\n", x[j+1]);
                    fprintf(file,"Akarnya : %lg\n", x[j+1]);
                x0[n]=x[j+1];
                n++;
            }
        }
    }
}

void newtonRaphson(){
    j=0;
    i=0;
    while(i < n){
        printf("=================================================\n");
        printf("%2s|   %-8s |  %-8s     | %-7s|\n","i","x0","fungsi(x0)","diffungsi(x0)");
        printf("=================================================\n");
            fprintf(file,"=================================================\n");
            fprintf(file,"%2s|   %-8s |  %-8s     | %-7s|\n","i","x0","fungsi(x0)","diffungsi(x0)");
            fprintf(file,"=================================================\n");
        do{
            x1 = x0[i] - (fungsix(x0[i])/diffungsix(x0[i]));
            printf("%2d| %-11lg| %-13lg   |%-12lg  |\n",j+1,x0[i],fungsix(x0[i]),diffungsix(x0[i]));
                fprintf(file,"%2d| %-11lg| %-13lg   |%-12lg  |\n",j+1,x0[i],fungsix(x0[i]),diffungsix(x0[i]));
            err = fabs(fungsix(x0[i]));
            x0[i]=x1;
            j++;
        }while( j < N && err >= e);
        printf("=================================================\n");
        printf("akar terletak di %lg dengan nilai %lg\n", x1, fungsix(x1));
            fprintf(file,"=================================================\n");
            fprintf(file,"akar terletak di %lg dengan nilai %lg\n", x1, fungsix(x1));
        i++;
    }
}

void title(){
    printf("===========================================================\n");
    printf("METODE NEWTON RAPHSON MODIFIKASI TABEL By Mirra Ariesta A.A");
    printf("\n===========================================================\n");
        fprintf(file,"===========================================================\n");
        fprintf(file,"METODE NEWTON RAPHSON MODIFIKASI TABEL By Mirra Ariesta A.A");
        fprintf(file,"\n===========================================================\n");
}


main(){
    file = fopen("reportNewtonRaphsonTabel.txt","w");
    char pilih;
    title();
    do{
        input();
        tabel();
        newtonRaphson();
        printf("\n============================\n\n");
            fprintf(file,"\n============================\n\n");
        fflush(stdin);
        printf("Ulangi [y/t] ? :");
        scanf("%c", &pilih);
    }
    while(pilih=='y'||pilih=='Y');
}