add

public/c/ch3/image/get2Len.c

@@ -0,0 +1,30 @@
+#include <stdio.h>
+#include <math.h>
+int binaryLength1(int i) {
+    if (i == 0) return 1; 
+    int k = 1;
+    i = i / 2;
+    while (i > 0) {
+        k++;
+        i = i / 2;
+    }
+    return k;
+}
+int binaryLength2(int n) {
+    if (n == 0) return 1; 
+    return (int)(log2(n)) + 1; 
+}
+int binaryLength3(int n) {
+    if (n == 0) return 1; 
+    int length = 0;
+    while (n > 0) {
+        n >>= 1; // 右移一位，相当于除以2
+        length++;
+    }
+    return length;
+}
+int main(){
+    printf("%d\n",binaryLength1(8));
+    printf("%d\n",binaryLength2(8));
+    printf("%d\n",binaryLength3(8));
+}