2nd_Sem_Bogachev/2025.04.18/dist/Ulyanov_MT/task01.c

95 lines
2.1 KiB
C

#include <stdio.h>
#include <stdlib.h>
#include <time.h>
#include <math.h>
#include "io_status.h"
#include "array.h"
#include "functions.h"
io_status solve1(double*, double*, double, int, double*);
int main(int argc, char* argv[])
{
int task = 1;
io_status ret;
double* x;
double* y;
int n;
double x0;
char* name = 0;
double res;
double t;
if (!((argc == 4) && sscanf(argv[1], "%le", &x0) == 1 && sscanf(argv[2], "%d", &n) == 1))
{
printf("Usage: %s x0 n file\n", argv[0]);
return 1;
}
name = argv[3];
x = (double*) malloc(n * sizeof(double));
y = (double*) malloc(n * sizeof(double));
if ((!x) || (!y))
{
printf("Not enough memory\n");
if (x) free(x);
if (y) free(y);
return 2;
}
ret = read_function(x, y, n, name);
if (ret != SUCCESS)
{
switch(ret)
{
case ERROR_OPEN:
printf("Can not open file %s\n", name);
break;
case ERROR_READ:
printf("Can not read file %s\n", name);
break;
default:
printf("UNknown error in file %s\n", name);
}
free(x);
free(y);
return 3;
}
t = clock();
ret = solve1(x, y, x0, n, &res);
t = (clock() - t) / CLOCKS_PER_SEC;
if (ret != SUCCESS)
{
printf("Similar points in file %s\n", name);
free(x);
free(y);
return 4;
}
printf ("%s : Task = %d Result = %e Elapsed = %.2f\n", argv[0], task, res, t);
free(x);
free(y);
return 0;
}
io_status solve1(double* x, double* y, double x0, int n, double* res)
{
int i, j;
double el_i, el_j, mult, sum = 0;
for (i = 0; i < n; i++)
{
mult = 1;
el_i = x[i];
for (j = 0; j < i; j++)
{
el_j =x[j];
if (equal(el_i, el_j)) return ERROR_FUNCTION;
mult *= (x0 - el_j) / (el_i - el_j);
}
for (j = i + 1; j < n; j++)
{
el_j =x[j];
if (equal(el_i, el_j)) return ERROR_FUNCTION;
mult *= (x0 - el_j) / (el_i - el_j);
}
sum += y[i] * mult;
}
*res = sum;
return SUCCESS;
}