引入

Chap_8-find/lead_in/afind.c

@@ -0,0 +1,41 @@
+#include <stdio.h>
+
+#define N   10
+
+int sfind(int a[], int len, int key)
+{
+    for (int *p = a; p != &a[len]; ++p)
+        if (*p == key) return p - a;
+    // for (int i = 0; i < len; ++i)
+    //     if (key == a[i]) return i;
+
+    return -1;
+}
+
+int bfind(int a[], int len, int key)
+{
+    int l, h, m;
+
+    l = 0;
+    h = len - 1;
+    while (l <= h)
+    {
+        m = (l + h) / 2; // m = (l + h) >> 1;
+        if (key == a[m]) return m;
+        else if (key < a[m]) h = m - 1;
+        else l = m + 1;
+    }
+
+    return -1;
+}
+
+int main()
+{
+    int x[N] = {0, 1, 2, 3, 4, 5, 6, 7, 8, 9};
+    int k = 5;
+
+    printf(sfind(x, N, k) >= 0 ? "sfind found\n" : "sfind not found\n");
+    printf(bfind(x, N, k) >= 0 ? "bfind found\n" : "bfind not found\n");
+
+    return 0;
+}