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  1. #include <stdio.h>
  2. #include <stdlib.h>
  3.  
  4. void readPolynom(int **p, int *n) {
  5.     printf("Give the degree of the polynom -> ");
  6.     scanf("%d", n);
  7.  
  8.     // Allocate memory for coefficients (degree + 1 elements)
  9.     *p = (int *)malloc((*n + 1) * sizeof(int));
  10.     if (*p == NULL) {
  11.         printf("Memory allocation failed!\n");
  12.         exit(1);
  13.     }
  14.  
  15.     for(int i = 0; i <= *n; i++) {
  16.         printf("P[%d] = ", i);
  17.         scanf("%d", (*p + i));
  18.     }
  19. }
  20.  
  21. void writePolynom(int *p, int *n) {
  22.     printf("p(x) = %dx^0", p[0]);
  23.     for(int i = 1; i <= *n; i++) {
  24.         printf(" + %dx^%d", p[i], i);
  25.     }
  26. }
  27.  
  28. float valuePolynom(int *p, int *n, float x) {
  29.     float value = p[0],
  30.           aux = 1;
  31.  
  32.     for(int i = 1; i <= *n; ++i) {
  33.         aux = aux * x;
  34.         value += aux * p[i];
  35.     }
  36.  
  37.     return value;
  38. }
  39.  
  40. void derivatePolynom(int *p, int *n) {
  41.     for(int i = 0; i < *n; i++) {
  42.         p[i] = p[i + 1] * (i + 1);
  43.     }
  44.     (*n)--;
  45. }
  46.  
  47. int main(int argc, char const *argv[]) {
  48.     int *coef = NULL;  // Dynamic array for coefficients
  49.     int n;             // Degree
  50.  
  51.     readPolynom(&coef, &n);
  52.     writePolynom(coef, &n);
  53.     derivatePolynom(coef, &n);
  54.     printf("\n\n");
  55.     writePolynom(coef, &n);
  56.  
  57.     float x = 1.450;
  58.     float ans = valuePolynom(coef, &n, x);
  59.     printf("\np(%.3f) = %.3f\n", x, ans);
  60.  
  61.     // Free allocated memory
  62.     free(coef);
  63.     return 0;
  64. }
Success #stdin #stdout 0s 5284KB
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stdout
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Give the degree of the polynom -> P[0] = P[1] = P[2] = P[3] = p(x) = 2x^0 + 3x^1 + 4x^2 + 0x^3

p(x) = 3x^0 + 8x^1 + 0x^2
p(1.450) = 14.600
https://ideone.com/Zu1Xp4
Derivative of a polynomial / Derivata unui polinom.
language:
C (gcc 8.3)
created:
113 days ago
visibility:
secret

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