comb.h

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/* COMB.H */

#ifndef _COMB_H_
#define _COMB_H_


typedef struct {
  int *numbers;
  int n;
  int *curr;
  int *next;
  int r;
  int *x;
  int last;
} combinations; 


combinations *new_combinations(int numbers[], int n, int r);
/*
 * Makes a combinations record which can be used in successive calls
 *   to next_combination() in order to go through all the combinations
 *   of length r from a set of numbers of length n.
 */

static int incr(int *x, int n, int r);
/*
 * Increments combination pointers.
 *   Returns 0 iff the input was the last combination.
 */

int *next_combination(combinations *bob);
/*
 * Returns a pointer to an array of integers describing the next
 *   combination of the array of numbers stored in (bob).
 */

void close_combinations(combinations *bob);
/*
 * Frees some memory.
 */

#endif

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