实验3_C语言函数应用编程

Task1

 1 #include <stdio.h>
 2 #include <stdlib.h>
 3 #include <time.h>
 4 #include <windows.h>
 5 #define N 80
 6 
 7 void print_text(int line, int col, char text[]); 
 8 void print_spaces(int n);
 9 void print_blank_lines(int n); 
10 
11 int main() {
12     int line, col, i;
13     char text[N] = "hi, April~";
14     
15     srand(time(0));
16     
17     for(i = 1; i <= 10; ++i) {
18         line = rand() % 25;
19         col =  rand() % 80;
20         print_text(line, col, text);
21         Sleep(1000);
22     }
23     
24     return 0; 
25 }
26 
27 void print_spaces(int n) {
28     int i;
29     
30     for(i = 1; i <= n; ++i)
31         printf(" ");
32 }
33 
34 void print_blank_lines(int n) {
35     int i;
36     
37     for(i = 1; i <= n; ++i)
38         printf("\n");
39  } 
40 
41 void print_text(int line, int col, char text[]) {
42     print_blank_lines(line-1); 
43     print_spaces(col-1);
44     printf("%s", text);
45 }

该程序运行后在屏幕上每隔1s随机输出一个“hi，April~”（由函数控制打印空行、空列），共输出10个。

Task2

2-1

 1 #include <stdio.h>
 2 #include<stdlib.h>
 3 long long fac(int n);
 4 
 5 int main() {
 6     int i, n;
 7 
 8     printf("Enter n: ");
 9     scanf("%d", &n);
10 
11     for (i = 1; i <= n; ++i)
12         printf("%d! = %lld\n", i, fac(i));
13     system("pause");
14     return 0;
15 }
16 
17 long long fac(int n) {
18     static long long p = 1;
19     printf("p=%11d\n",p);
20     p = p * n;
21     
22     return p;
23 }

2-2

 1 #include <stdio.h>
 2 #include<stdlib.h>
 3 int func(int, int);    
 4 
 5 int main() {
 6     int k = 4, m = 1, p1, p2;
 7 
 8     p1 = func(k, m); //func(4,1)  i=2+0+1=3  p1=3+4+1=8
 9     p2 = func(k, m); //func(4,8)  i=3+8+1=12 p2=12+4+1=17
10     printf("%d, %d\n", p1, p2);
11     system("pause");
12     return 0;
13 }
14 
15 int func(int a, int b) {
16     static int m = 0, i = 2;
17 
18     i += m + 1;
19     m = i + a + b;
20 
21     return m;
22 }

局部变量的值保持不变，程序计算过程如注释所示。

Task3

 1 #include <stdio.h>
 2 #include<stdlib.h>
 3 long long func(int n);
 4 
 5 int main() {
 6     int n;
 7     long long f;
 8 
 9     while (scanf("%d", &n) != EOF) {
10         f = func(n); 
11         printf("n = %d, f = %lld\n", n, f);
12     }
13     system("pause");
14     return 0;
15 }
16 
17 long long func(int n){
18     if (n==0)
19         return 0;
20     else
21         return 2*(func(n-1)+1)-1;
22 }

Task4

4-1（迭代）

 1 #include <stdio.h>
 2 #include<stdlib.h>
 3 //迭代
 4 int func(int n, int m);
 5 
 6 int main() {
 7     int n, m;
 8 
 9     while(scanf("%d%d", &n, &m) != EOF)
10         printf("n = %d, m = %d, ans = %d\n", n, m, func(n, m));
11     system("pause");
12     return 0;
13 }
14 
15 int func(int n, int m){
16     int i=0,ans=1;
17     if (m>n)
18         return 0;
19     else
20     for(;i<m;i++)
21     {
22         ans*=(n-i);
23         ans/=(i+1);
24     }
25     return ans;
26 }

4-2（递归）

 1 #include <stdio.h>
 2 int func(int n, int m);
 3 
 4 int main() {
 5     int n, m;
 6 
 7     while (scanf_s("%d%d", &n, &m) != EOF)
 8         printf("n = %d, m = %d, ans = %d\n", n, m, func(n, m));
 9 
10     return 0;
11 }
12 int func(int n, int m) {
13     if (m == 0 || m == n)
14         return 1;
15     else if (m > n)
16         return 0;
17     else
18         return func(n - 1, m - 1) + func(n-1, m );
19 }

Task5

 1 #include <stdio.h>
 2 #include<stdlib.h>
 3 
 4 void hanoi(unsigned int n, char from, char temp, char to, int* m);
 5 void moveplate(unsigned int n, char from, char to, int* m);
 6 int main()
 7 {
 8     unsigned int n;
 9     while (scanf_s("%u", &n) != EOF)
10     {
11         int m = 0;
12         hanoi(n, 'A', 'B', 'C', &m);
13         printf("\n一共移动了%d次.\n\n", m);
14     }
15     system("pause");
16     return 0;
17 }
18 
19 void hanoi(unsigned int n, char from, char temp, char to, int* m)
20 {
21     if (n == 1)
22         moveplate(n, from, to, m);
23     else
24     {
25         hanoi(n - 1, from, to, temp, m);
26         moveplate(n, from, to, m);
27         hanoi(n - 1, temp, from, to, m);
28     }
29 }
30 void moveplate(unsigned int n, char from, char to, int* m)
31 {
32     printf("%u:%c --> %c\n", n, from, to);
33     ++(*m);
34 }

Task6

 1 #include <stdio.h>
 2 #include <math.h>
 3 #include<stdlib.h>
 4 long func(long s);
 5 int main() {
 6 
 7     long s, t;
 8 
 9     printf("Enter a number: ");
10     while (scanf("%ld", &s) != EOF) {
11         t = func(s);
12         printf("new number is: %ld\n\n", t);
13         printf("Enter a number: ");
14     }
15     system("pause");
16     return 0;
17 }
18 
19 long func(long s){
20     int ans=0,x=1;
21     if (s==0)
22         return 0;
23     while(s>0)
24         {
25         int m=s%10;
26         if(m%2!=0){
27             ans+=x*m;
28             x*=10;
29         }
30         s/=10;
31         }
32         return ans;
33 }

实验总结

需要理解迭代和递归的基本思路，认清问题的本质，学会用不同方法解决问题。