fork download
copy 
  1. #include <stdio.h>
  2. #include <stdlib.h>
  3. #include <stddef.h> // size_t
  4. #include <math.h>
  5.  
  6. #define MAX_SIZE 20
  7.  
  8. #define MAX_ITERATOR 200
  9. #define EPS 1E-9
  10. #define FILENAME "input.txt"
  11.  
  12.  
  13. // 代入 C[size], r
  14. // 求 f(r) = C0 + C1/(1+r)1 + C2/(1+r)2 + C3/(1+r)3 + ... + Cn/(1+r)n
  15. double IRR_func(double *C, size_t size, double r)
  16. {
  17. 	size_t n;
  18. 	double r1 = (1.0+r);
  19. 	double rn = r1;
  20. 	double sum = C[0];
  21. 	for(n=1; n<size; ++n){
  22. 		sum+= C[n]/rn;
  23. 		rn*=r1; // rn = (1+r)^n
  24. 	}
  25. 	return sum;
  26. }
  27.  
  28. // -------------------------------------------------------
  29. double BiSector(
  30. 	double *C,              /* 每期金流  */
  31. 	size_t n,               /* 共 n 期 */
  32. 	double low,             /*   r下界  */
  33. 	double up,              /*   r上界  */
  34. 	double (*fx)(double*, size_t ,double ),/* 適應函式*/
  35. 	double eps,             /* 容許誤差*/
  36. 	int max_itera)          /* 最大迭代*/
  37. {
  38. 	double mid, y;
  39. 	double yup = fx(C, n, up);
  40.  
  41. 	if( yup *fx(C, n, low) > 0.0) {
  42. 		printf("\n>   has no root at [%lf, %lf]", low, up);
  43. 		return low;
  44. 	}
  45. 	do{
  46. 		mid = (low+up)*0.5;
  47. 		y   = fx(C, n, mid);
  48. 		if(y * yup <= 0.0) low = mid;
  49. 		else up = mid, yup=y;
  50. 		--max_itera;
  51. 	}while(max_itera && fabs(y) > eps);
  52. 	return mid;
  53. }
  54.  
  55. //
  56. int main()
  57. {
  58.  
  59. 	double C[MAX_SIZE] = {0.0}; 
  60. 	size_t i, cnt=0;
  61. 	double Rate=0.0;
  62.  
  63. 	// read from file.
  64. 	FILE *fp = fopen(FILENAME, "r");
  65. 	if(fp==NULL){
  66. 		printf("open %s file fail.\n", FILENAME);
  67. 		getchar();
  68. 		return EXIT_FAILURE;
  69. 	}
  70. 	while(fscanf(fp, "%u", &cnt)==1){
  71. 		// read a line
  72. 		if(cnt==0) break;
  73. 		++cnt;
  74. 		for(i=0; i<cnt; ++i)
  75. 			fscanf(fp, "%lf", &C[i]);
  76. 		// process
  77. 		Rate = BiSector(C, cnt, 0.0, 1.0, IRR_func, EPS, MAX_ITERATOR);
  78. 		printf("%lf %%\n", Rate * 100.0);
  79. 	}
  80. 	fclose(fp);
  81.  
  82. 	system("pause");
  83. 	return EXIT_SUCCESS;
  84. }
Runtime error #stdin #stdout 0.01s 1856KB
comments (?)
stdin
copy 
Standard input is empty
stdout
copy 
open input.txt file fail.
https://ideone.com/bQaGd
language:
C (gcc 8.3)
created:
13 years ago
visibility:
public

Share or Embed source code

Discover > Sphere Engine API

The brand new service which powers Ideone!

Discover > IDE Widget

Widget for compiling and running the source code in a web browser!