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  1. #include<stdio.h>
  2. #include<stdlib.h>
  3.  
  4. int permutation(char nchars[], char result[], int count, int max);
  5. void arrayPrint(char a[], int count);
  6.  
  7. int permutation(char nchars[], char result[], int count, int max) {
  8. 	int i;
  9. 	int j;
  10. 	char *remain;
  11.  
  12. 	if (count == max) {
  13. 		arrayPrint(result, max);
  14. 		return EXIT_SUCCESS;
  15. 	}
  16.  
  17. 	for (i = 0; i < max - count; i++) {		
  18. 		remain = calloc(max - count, sizeof(char));
  19.  
  20. 		for (j = 0; j < max - count; j++) {
  21. 			remain[j] = nchars[j];
  22. 		}
  23.  
  24. 		result[count] = remain[i];
  25.  
  26. 		for (j = i + 1; j < max - count; j++) {
  27. 			remain[j - 1] = remain[j];
  28. 		}
  29.  
  30. 		permutation(remain, result, count + 1, max);
  31.  
  32. 		free(remain);
  33. 	}
  34.  
  35. 	return EXIT_SUCCESS;
  36. }
  37.  
  38. void arrayPrint(char a[], int count) {
  39. 	int i;
  40.  
  41. 	for (i = 0; i < count; i++) {
  42. 		printf("%c", a[i]);
  43. 		if (i < count - 1) {
  44. 			printf(",");
  45. 		} else {
  46. 			printf("\n");
  47. 		}
  48. 	}
  49. }
  50.  
  51. int main(int argc, char *argv[]) {
  52. 	char *chars = "abcdefghijklmno";
  53. 	char *nchars;
  54. 	char *result;
  55. 	int n;
  56. 	int i;
  57.  
  58. 	/* n = atoi(argv[1]); */
  59. 	n = 5;
  60.  
  61. 	nchars = calloc(n, sizeof(char));
  62. 	result = calloc(n, sizeof(char));
  63.  
  64. 	for (i = 0; i < n; i++) {
  65. 		nchars[i] = chars[i];
  66. 	}
  67.  
  68. 	permutation(nchars, result, 0, n);
  69.  
  70. 	free(result);
  71. 	free(nchars);
  72.  
  73. 	return EXIT_SUCCESS;
  74. }
Success #stdin #stdout 0.01s 1852KB
comments (?)
stdin 
Standard input is empty
stdout 
a,b,c,d,e
a,b,c,e,d
a,b,d,c,e
a,b,d,e,c
a,b,e,c,d
a,b,e,d,c
a,c,b,d,e
a,c,b,e,d
a,c,d,b,e
a,c,d,e,b
a,c,e,b,d
a,c,e,d,b
a,d,b,c,e
a,d,b,e,c
a,d,c,b,e
a,d,c,e,b
a,d,e,b,c
a,d,e,c,b
a,e,b,c,d
a,e,b,d,c
a,e,c,b,d
a,e,c,d,b
a,e,d,b,c
a,e,d,c,b
b,a,c,d,e
b,a,c,e,d
b,a,d,c,e
b,a,d,e,c
b,a,e,c,d
b,a,e,d,c
b,c,a,d,e
b,c,a,e,d
b,c,d,a,e
b,c,d,e,a
b,c,e,a,d
b,c,e,d,a
b,d,a,c,e
b,d,a,e,c
b,d,c,a,e
b,d,c,e,a
b,d,e,a,c
b,d,e,c,a
b,e,a,c,d
b,e,a,d,c
b,e,c,a,d
b,e,c,d,a
b,e,d,a,c
b,e,d,c,a
c,a,b,d,e
c,a,b,e,d
c,a,d,b,e
c,a,d,e,b
c,a,e,b,d
c,a,e,d,b
c,b,a,d,e
c,b,a,e,d
c,b,d,a,e
c,b,d,e,a
c,b,e,a,d
c,b,e,d,a
c,d,a,b,e
c,d,a,e,b
c,d,b,a,e
c,d,b,e,a
c,d,e,a,b
c,d,e,b,a
c,e,a,b,d
c,e,a,d,b
c,e,b,a,d
c,e,b,d,a
c,e,d,a,b
c,e,d,b,a
d,a,b,c,e
d,a,b,e,c
d,a,c,b,e
d,a,c,e,b
d,a,e,b,c
d,a,e,c,b
d,b,a,c,e
d,b,a,e,c
d,b,c,a,e
d,b,c,e,a
d,b,e,a,c
d,b,e,c,a
d,c,a,b,e
d,c,a,e,b
d,c,b,a,e
d,c,b,e,a
d,c,e,a,b
d,c,e,b,a
d,e,a,b,c
d,e,a,c,b
d,e,b,a,c
d,e,b,c,a
d,e,c,a,b
d,e,c,b,a
e,a,b,c,d
e,a,b,d,c
e,a,c,b,d
e,a,c,d,b
e,a,d,b,c
e,a,d,c,b
e,b,a,c,d
e,b,a,d,c
e,b,c,a,d
e,b,c,d,a
e,b,d,a,c
e,b,d,c,a
e,c,a,b,d
e,c,a,d,b
e,c,b,a,d
e,c,b,d,a
e,c,d,a,b
e,c,d,b,a
e,d,a,b,c
e,d,a,c,b
e,d,b,a,c
e,d,b,c,a
e,d,c,a,b
e,d,c,b,a
https://ideone.com/ky3Ok
language:
C (gcc 8.3)
created:
11 years ago
visibility:
public

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