inital commit

1 files changed, 56 insertions, 0 deletions

diff --git a/3.1.c b/3.1.c
new file mode 100644
index 0000000..25e2ca1
--- /dev/null
+++ b/3.1.c
@@ -0,0 +1,56 @@
+#include <stdio.h>
+
+int binsearch(int x, int v[], int n);
+int binsearch2(int x, int v[], int n);
+
+int 
+main(void)
+{
+  int v[10]= {1, 2, 3, 4, 5, 6, 7, 8, 9, 11};
+  printf("%d\n", binsearch(v[5], v, 10));
+}
+
+int 
+binsearch(int x, int v[], int n) 
+{
+  int low, high, mid;
+
+  low = 0;
+  high = n-1;
+
+  while (low <= high) {
+    mid = (low+high)/2;
+
+    if (x < v[mid])
+      high = mid - 1;
+    else if (x > v[mid])
+      low  = mid + 1;
+    else 
+      return mid;
+  }
+
+  return -1;
+}
+
+int 
+binsearch2(int x, int v[], int n) 
+{
+  int low, high, mid;
+
+  low = 0;
+  high = n-1;
+
+  while (low < high) {
+    mid = (low+high)/2;
+
+    if (x <= v[mid])
+      high = mid;
+    else 
+      low = mid+1;
+
+  }
+
+  /* here low == high */
+  
+  return (x == v[low]) ? low : -1; 
+}