实验三
实验任务1
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[]); // 函数声明 8 void print_spaces(int n); // 函数声明 9 void print_blank_lines(int n); // 函数声明 10 11 int main() { 12 int line, col, i; 13 char text[N] = "hi, April~"; 14 15 srand(time(0)); // 以当前系统时间作为随机种子 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); // 暂停1000ms 22 } 23 24 return 0; 25 } 26 27 // 打印n个空格 28 void print_spaces(int n) { 29 int i; 30 31 for(i = 1; i <= n; ++i) 32 printf(" "); 33 } 34 35 // 打印n行空白行 36 void print_blank_lines(int n) { 37 int i; 38 39 for(i = 1; i <= n; ++i) 40 printf("\n"); 41 } 42 43 // 在第line行第col列打印一段文本 44 void print_text(int line, int col, char text[]) { 45 print_blank_lines(line-1); // 打印(line-1)行空行 46 print_spaces(col-1); // 打印(col-1)列空格 47 printf("%s", text); // 在第line行、col列输出text中字符串 48 }
10秒内每秒在随机位置输出一个“hi,April~”
实验任务二
1 // 利用局部static变量的特性,计算阶乘 2 3 #include <stdio.h> 4 long long fac(int n); // 函数声明 5 6 int main() { 7 int i, n; 8 9 printf("Enter n: "); 10 scanf("%d", &n); 11 12 for (i = 1; i <= n; ++i) 13 printf("%d! = %lld\n", i, fac(i)); 14 15 system("pause"); 16 return 0; 17 } 18 19 // 函数定义 20 long long fac(int n) { 21 static long long p = 1; 22 printf("p = %lld\n",p);//打印局部变量p的值 static变量保留上一个过程操作后的p(即为(n-1)!的值)作为初始p的值 23 24 p = p * n; 25 26 return p; 27 }

// 练习:局部static变量特性 #include <stdio.h> int func(int, int); // 函数声明 int main() { int k = 4, m = 1, p1, p2; p1 = func(k, m); // 函数调用 p2 = func(k, m); // 函数调用 printf("%d, %d\n", p1, p2); system("pause"); return 0; } // 函数定义 //与分析结果一致 int func(int a, int b) { static int m = 0, i = 2; i += m + 1; m = i + a + b; return m; }

一致
实验任务三
1 #include <stdio.h> 2 long long func(int n); // 函数声明 3 4 int main() { 5 int n; 6 long long f; 7 8 while (scanf("%d", &n) != EOF) { 9 f = func(n); // 函数调用 10 printf("n = %d, f = %lld\n", n, f); 11 } 12 13 return 0; 14 } 15 16 // 函数定义 17 long long func(int n){ 18 long long f; 19 if((n-1)>=0) 20 f = 2 * func(n-1) + 1; 21 if((n-1)==0) 22 f = 1; 23 if(n==0) 24 f = 0; 25 26 return f; 27 }

实验任务四
1 #include <stdio.h> 2 int func(int n, int m); 3 4 int main() { 5 int n, m; 6 7 while(scanf("%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 13 // 函数定义 14 int func(int n, int m){ 15 int ans; 16 if ( m > n ) 17 ans = 0; 18 else if ( m == n ) 19 ans = 1; 20 else if ( m < n ){ 21 if ( m == 0 ) 22 ans =1; 23 if ( m != 0 ) 24 ans = func(n-1,m) + func(n-1,m-1); 25 } 26 27 return ans; 28 }

实验任务五
#include <stdio.h> double mypow(int x, int y); // 函数声明 int main() { int x, y; double ans; while(scanf("%d%d", &x, &y) != EOF) { ans = mypow(x, y); // 函数调用 printf("%d的%d次方: %g\n\n", x, y, ans); } return 0; } // 函数定义 double mypow(int x, int y){ double ans = 1.0; double k = 1.0 / x ; if (y > 0){ for(int i = 1; i <= y; i++) ans *= (double)x ; } if (y == 0) ans = 1.0 ; if (y < 0) for (int j = y;j < 0 ;j++) ans *= k ; return ans ; }

实验任务六
1 #include <stdio.h> 2 #include <stdlib.h> 3 4 void hanoi(unsigned int n, char from, char temp, char to); 5 void moveplate(unsigned int n, char from, char to); 6 7 int tot; 8 9 int main() { 10 unsigned int n; 11 12 while(scanf("%u", &n) != EOF) { 13 tot = 0; 14 15 hanoi(n, 'A', 'B', 'C'); 16 17 printf("一共移动了%d次\n", tot); 18 } 19 20 system("pause"); 21 22 return 0; 23 } 24 25 void hanoi(unsigned int n, char from, char temp, char to) { 26 if(n == 1) 27 moveplate(n, from, to); 28 else { 29 hanoi(n - 1, from, to, temp); 30 moveplate(n, from, to); 31 hanoi(n - 1, temp, from, to); 32 } 33 } 34 35 void moveplate(unsigned int n, char from, char to) { 36 tot ++; 37 printf("%u: %c --> %c\n", n, from, to); 38 }

实验任务七
1 #include <stdio.h> 2 #include <math.h> 3 int is_prime(int n); 4 int main(){ 5 int n = 20; 6 int num1,num2,z; 7 for (int f = 2;f <= n; f = f+2 ){ 8 for (int p = 2;p <= f/2;p++){ 9 if ( is_prime(p) == 1 ){ 10 num1 = p; 11 z = f - num1; 12 if( is_prime(z) == 1){ 13 num2 = z; 14 printf("%d = %d + %d\n",f,num1,num2); 15 } 16 } 17 if( is_prime(z) == 1){ 18 break; 19 } 20 } 21 } 22 return 0; 23 } 24 25 int is_prime(int p){ 26 int flag = 1; 27 for(int j = 2;j <= sqrt(p);j++){ 28 if ( p % j == 0){ 29 flag = 0; 30 break; 31 } 32 } 33 return flag; 34 }

实验任务八
#include <stdio.h> #include <math.h> long func(long s); int main() { long s, t; printf("Enter a number: "); while(scanf("%ld", &s) != EOF) { t = func(s); printf("new number is:%ld\n\n", t); printf("Enter a number: "); } return 0; } long func(long s) { long t = 0, t1 = 0; while(s > 0) { int tmp = s % 10; s /= 10; if(tmp % 2 == 1) t1 = t1 * 10 + tmp; } while(t1 > 0) { t = t * 10 + (t1 % 10); t1 /= 10; } return t; }

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