init commit

archive/algorithm/problem/n!.c

@@ -0,0 +1,63 @@
+#include <stdio.h>
+// 使用栈的方式计算阶乘
+struct stack
+{
+    int val[100];
+    int pos;
+} s;
+
+void push(int i)
+{
+    s.val[s.pos++] = i;
+}
+
+int pop()
+{
+    if (s.pos == 0)
+    {
+        return 0;
+    }
+    return s.val[--s.pos];
+}
+
+int fac2(int n)
+{
+    int result = 1;
+    for (int i = n; i > 0; i--)
+    {
+        result *= i;
+    }
+    return result;
+}
+
+int fac1(int n)
+{
+    if (n == 1)
+        return 1;
+    else
+        return n * fac1(n - 1);
+}
+
+//这算么？
+int fac3(int n)
+{
+    do
+    {
+        push(n);
+    } while (--n);
+
+    int i = 0, result = 1;
+    while (i = pop())
+    {
+        result *= i;
+    }
+    return result;
+}
+
+int main()
+{
+    printf("%d\n", fac1(10));
+    printf("%d\n", fac2(10));
+    printf("%d", fac3(10));
+    getchar();
+}