Use BSearch and QSort in
1. Determine the order relationship of the comparative object;
2, the comparison function always uses two const void * parameters;
3. Conversion of the parameters correctly to the pointer to the type element type when the function begins;
4, in the first parameter is greater than, equal to, 2, 0, -1, respectively, when less than the second;
5, pay attention to the way of use.
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Example: Assume that is sorted is an integer array. Define comparison functions:
INT ICMP (const void * p, const void * q) {
Const Int * m = p, * n = q;
RETURN * m> * n? 1: (* m == * n? 0: -1);
}
use:
INT * P, A [] = {5, 6, 3, 28, 23, 34, 7, 9, 6, 14}, k = 7;
Int main () {
...
Qsort (A, SizeOf (a) / sizeof (int), sizeof (int), ICMP);
/ * In this way, the elements of array A have been arranged in the rising order * /
P = BSearch (& K, A, SIZEOF (A) / Sizeof (int), Sizeof (int), ICMP);
/ * Pointer P will point to the position of the element 7 in array A * /
...
}
