diff --git a/pset8/1-values.c b/pset8/1-values.c
new file mode 100644
index 0000000..cb0c1bc
--- /dev/null
+++ b/pset8/1-values.c
@@ -0,0 +1,21 @@
+// #include <stdio.h>
+// 
+// int fuc(int n);
+// 
+// int main() {
+//   int n;
+// 
+//   scanf("%d", &n);
+//   printf("%d\n", fuc(n));
+// 
+//   return 0;
+// }
+
+/* 请在这里填写答案 */
+int fuc(int n) {
+  if (n == 0) {
+    return 0;
+  } else {
+    return fuc(n - 1) + n * n * n;
+  }
+}
diff --git a/pset8/2-getSum.c b/pset8/2-getSum.c
new file mode 100644
index 0000000..8d69852
--- /dev/null
+++ b/pset8/2-getSum.c
@@ -0,0 +1,21 @@
+// #include <stdio.h>
+// 
+// int getSum(int n, int a);
+// 
+// int main() {
+//   int n, a;
+// 
+//   scanf("%d%d", &n, &a);
+//   printf("%d\n", getSum(n, a));
+// 
+//   return 0;
+// }
+
+/* 请在这里填写答案 */
+int getSum(int n, int a) {
+	if (n == 0) {
+		return a;
+	} else {
+		return getSum(n - 1, a) + a + 3 * n;
+	}
+}
diff --git a/pset8/3-findMax.c b/pset8/3-findMax.c
new file mode 100644
index 0000000..55c8cf7
--- /dev/null
+++ b/pset8/3-findMax.c
@@ -0,0 +1,28 @@
+// #include <stdio.h>
+// 
+// int findMax(int n);
+// 
+// int main() {
+//   int n;
+// 
+//   scanf("%d", &n);
+//   printf("%d\n", findMax(n));
+// 
+//   return 0;
+// }
+
+/* 请在这里填写答案 */
+int findMax(int n) {
+  int input;
+  scanf("%d", &input);
+  if (n == 1) {
+    return input;
+  } else {
+    int tmp = findMax(n - 1);
+    if (input >= tmp) {
+      return input;
+    } else {
+      return tmp;
+    }
+  }
+}
diff --git a/pset8/4-convert.c b/pset8/4-convert.c
new file mode 100644
index 0000000..e44daea
--- /dev/null
+++ b/pset8/4-convert.c
@@ -0,0 +1,23 @@
+// #include <stdio.h>
+// 
+// int convert(int n);
+// 
+// int main() {
+//   int n;
+// 
+//   scanf("%d", &n);
+// 
+//   printf("%d\n", convert(n));
+//   return 0;
+// }
+
+/* 请在这里填写答案 */
+int convert(int n) {
+	if (n == 1)	{ // Base case
+		return 1;
+	} else if (n == 0) { // Base case
+		return 0;
+	} else {
+		return n % 10 + convert(n/10) * 2;
+	}
+}
diff --git a/pset8/5-countBinary.c b/pset8/5-countBinary.c
new file mode 100644
index 0000000..dd65bc7
--- /dev/null
+++ b/pset8/5-countBinary.c
@@ -0,0 +1,23 @@
+// #include <stdio.h>
+// 
+// int countBinary(int);
+// 
+// int main() {
+//   int n;
+// 
+//   scanf("%d", &n);
+//   printf("%d\n", countBinary(n));
+// 
+//   return 0;
+// }
+
+/* 请在这里填写答案 */
+int countBinary(int n) {
+  if (n == 0) {
+    return 1;
+  } else if (n == 1) {
+    return 1;
+  } else {
+    return 1 + countBinary(n / 2);
+  }
+}
diff --git a/pset8/6-eveluation.c b/pset8/6-eveluation.c
new file mode 100644
index 0000000..f83c362
--- /dev/null
+++ b/pset8/6-eveluation.c
@@ -0,0 +1,24 @@
+// #include <stdio.h>
+// 
+// int evaluation(int n, int a);
+// int main() {
+//   int n, a;
+// 
+//   scanf("%d%d", &n, &a);
+//   printf("%d\n", evaluation(n, a));
+// 
+//   return 0;
+// }
+
+/* 请在这里填写答案 */
+int evaluation(int n, int a) {
+  if (n == -1) {
+    return 1;
+  } else {
+    int an = 1;
+    for (int i = 0; i < n; i++) {
+      an *= a;
+    }
+    return a * an + evaluation(n - 1, a);
+  }
+}
diff --git a/pset8/7-gcd.c b/pset8/7-gcd.c
new file mode 100644
index 0000000..7b2c1c0
--- /dev/null
+++ b/pset8/7-gcd.c
@@ -0,0 +1,22 @@
+#include<stdio.h>
+
+int GCD(int a , int b );
+
+int main()
+{
+    int        a , b ;
+
+    scanf("%d%d", &a , &b );
+    printf( "%d\n" , GCD( a, b ) ) ;
+
+    return 0 ;    
+}
+
+/* 请在这里填写答案 */
+int GCD(int a , int b ) {
+    if (a % b != 0)  {
+        return GCD(b, a % b);
+    } else {
+        return b;
+    }
+}
diff --git a/pset8/8-reverse.c b/pset8/8-reverse.c
new file mode 100644
index 0000000..453a8e3
--- /dev/null
+++ b/pset8/8-reverse.c
@@ -0,0 +1,22 @@
+// #include <stdio.h>
+// 
+// void reverse(int n);
+// 
+// int main() {
+//   int n;
+// 
+//   scanf("%d", &n);
+//   reverse(n);
+//   printf("\n");
+//   return 0;
+// }
+
+/* 请在这里填写答案 */
+void reverse(int n) {
+	if (n < 10) {
+		printf("%d", n);
+	} else {
+		printf("%d", n % 10);
+		reverse(n / 10);
+	}
+}
diff --git a/pset8/9-printFactor.c b/pset8/9-printFactor.c
new file mode 100644
index 0000000..2cf94c5
--- /dev/null
+++ b/pset8/9-printFactor.c
@@ -0,0 +1,29 @@
+// #include <stdio.h>
+// 
+// void printFactor(int, int);
+// 
+// int main() {
+//   int a, b, i;
+// 
+//   scanf("%d%d", &a, &b);
+//   for (i = a; i <= b; i++)
+//     printFactor(i, 1);
+// 
+//   return 0;
+// }
+
+/* 请在这里填写答案 */
+void printFactor(int num, int fac) {
+  if (fac == 1) { // Start of the line
+    printf("%d=", num);
+    printFactor(num, 2);
+  } else if (num <= fac) { // End of the line
+    printf("%d\n", num);
+  } else if (num % fac == 0) { // The middle ones
+    printf("%d*", fac);
+    printFactor(num / fac, 2);
+  } else {
+    printFactor(num, fac + 1);
+  }
+  return;
+}