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#include <stdio.h>
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#include <stdlib.h>
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#include <math.h>
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#include <time.h>
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#define SQR(x) ((x) * (x))
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#define LMIN 1.0
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#define LMAX 5.0
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#define NTRIES 10
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void estrai(double punto[2], double l);
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int dentro_intersez(double punto[2], double l);
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double inserimento();
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int main() {
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srand48(time(NULL));
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double l = inserimento();
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double R = sqrt(2) * l / 2.0;
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double C1[2] = {0, 0};
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double C2[2] = {l, l};
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int i, N, try;
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int N_in = 0;
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double punto[2];
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FILE *out = fopen("errore.dat", "w");
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for(N = 10; N <= 1000000; N *= 10) {
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double avg = 0., avg_sqr = 0.;
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for(try = 0; try < NTRIES; try++) {
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N_in = 0;
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for(i = 0; i < N; i++) {
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estrai(punto, l);
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if(dentro_intersez(punto, l)) {
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N_in++;
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}
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}
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double A_MC = 8 * SQR(l) * N_in / (double) N;
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avg += A_MC;
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avg_sqr += SQR(A_MC);
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}
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avg /= NTRIES;
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avg_sqr /= NTRIES;
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double std_dev = sqrt((avg_sqr - avg*avg) / NTRIES);
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double A_th = 4 * SQR(l) * atan(2);
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printf("%lf %lf\n", A_th, avg); // commentata dopo aver controllato che il codice funziona
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fprintf(out, "%.5lf %.5lf\n", log10(N), log10(std_dev));
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}
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fclose(out);
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return 0;
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}
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void estrai(double punto[2], double l) {
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punto[0] = 2.0 * drand48() * l;
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punto[1] = drand48() * l;
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}
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int dentro_intersez(double punto[2], double l) {
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return (SQR(punto[0]) + 4 * SQR(punto[1]) < 4 * SQR(l) && punto[1] < punto[0]);
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}
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double inserimento() {
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double l = 0;
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while(l < LMIN || l > LMAX) {
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printf("Inserire un valore compreso tra 1 e 5\n");
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scanf("%lf", &l);
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}
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return l;
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}
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