实验三
实  验  1
1 #include <stdio.h> 2 3 char score_to_grade(int score); // 函数声明 4 5 int main() { 6 int score; 7 char grade; 8 9 while(scanf("%d", &score) != EOF) { 10 grade = score_to_grade(score); // 函数调用 11 printf("分数: %d, 等级: %c\n\n", score, grade); 12 } 13 14 return 0; 15 } 16 17 // 函数定义 18 char score_to_grade(int score) { 19 char ans; 20 21 switch(score/10) { 22 case 10: 23 case 9: ans = 'A'; break; 24 case 8: ans = 'B'; break; 25 case 7: ans = 'C'; break; 26 case 6: ans = 'D'; break; 27 default: ans = 'E'; 28 } 29 30 return ans; 31 }

问题1:接收得分并返还等级
问题2:无break结束判断,输出恒为E;双引号导致数据类型不匹配
实 验 2
1 #include <stdio.h> 2 3 int sum_digits(int n); // 函数声明 4 5 int main() { 6 int n; 7 int ans; 8 9 while(printf("Enter n: "), scanf("%d", &n) != EOF) { 10 ans = sum_digits(n); // 函数调用 11 printf("n = %d, ans = %d\n\n", n, ans); 12 } 13 14 return 0; 15 } 16 17 // 函数定义 18 int sum_digits(int n) { 19 int ans = 0; 20 21 while(n != 0) { 22 ans += n % 10; 23 n /= 10; 24 } 25 26 return ans; 27 }

问题1:接收整数n并返还n各数位上数的和
问题2:能;原算法为迭代,新算法为递归
实 验 3
1 #include <stdio.h> 2 3 int power(int x, int n); // 函数声明 4 5 int main() { 6 int x, n; 7 int ans; 8 9 while(printf("Enter x and n: "), scanf_s("%d%d", &x, &n) != EOF) { 10 ans = power(x, n); // 函数调用 11 printf("n = %d, ans = %d\n\n", n, ans); 12 } 13 14 return 0; 15 } 16 17 // 函数定义 18 int power(int x, int n) { 19 int t; 20 21 if(n == 0) 22 return 1; 23 else if(n % 2) 24 return x * power(x, n-1); 25 else { 26 t = power(x, n/2); 27 return t*t; 28 } 29 }

问题1:计算x的n次方
问题2:是;

实 验 4
1 #include <stdio.h> 2 3 int is_prime(int n); 4 5 int main() 6 { 7 int all = 0; 8 printf("100以内的孪生素数:\n"); 9 for (int n = 1; n < 98; n++) 10 { 11 if (is_prime(n) && is_prime(n + 2)) 12 { 13 printf("%d %d\n", n, n + 2); 14 all++; 15 } 16 } 17 printf("100以内的孪生素数共有%d个", all); 18 return 0; 19 } 20 21 22 int is_prime(int n) 23 { 24 for (int i = 2; i < n; i++) 25 { 26 if (n % i == 0) 27 { 28 return 0; 29 } 30 } 31 if (n == 1) 32 { 33 return 0; 34 } 35 return 1; 36 }

实 验 5
迭代:
1 #include <stdio.h> 2 int func(int n, int m); // 函数声明 3 4 int main() { 5 int n, m; 6 int ans; 7 8 while(scanf_s("%d%d", &n, &m) != EOF) { 9 ans = func(n, m); // 函数调用 10 printf("n = %d, m = %d, ans = %d\n\n", n, m, ans); 11 } 12 13 return 0; 14 } 15 16 17 int func(int n, int m) 18 { 19 int ans; 20 int a = 1; 21 int b = 1; 22 int c = 1; 23 for (int i = 1; i <= n; i++) 24 { 25 a *= i; 26 } 27 for (int i = 1; i <= m; i++) 28 { 29 b *= i; 30 } 31 for (int i = 1; i <= n - m; i++) 32 { 33 c *= i; 34 } 35 ans = a / (b * c); 36 return ans; 37 }

递归:
1 #include <stdio.h> 2 int func(int n, int m); // 函数声明 3 4 int main() { 5 int n, m; 6 int ans; 7 8 while(scanf_s("%d%d", &n, &m) != EOF) { 9 ans = func(n, m); // 函数调用 10 printf("n = %d, m = %d, ans = %d\n\n", n, m, ans); 11 } 12 13 return 0; 14 } 15 16 17 int func(int n, int m) 18 { 19 int ans = 0; 20 if (m > n) 21 { 22 return 0; 23 } 24 else if (m == n || m == 0) 25 { 26 return 1; 27 } 28 else if (m == 1) 29 { 30 ans = n; 31 } 32 else 33 { 34 ans = func(n - 1, m) + func(n - 1, m - 1); 35 } 36 return ans; 37 }

实 验 6
1 #include <stdio.h> 2 3 int gcd(int a, int b, int c); 4 5 6 int main() 7 { 8 int a, b, c; 9 int ans; 10 11 while(scanf_s("%d%d%d", &a, &b, &c) != EOF) 12 { 13 ans = gcd(a, b, c); 14 printf("最大公约数: %d\n\n", ans); 15 } 16 17 return 0; 18 } 19 20 21 int gcd(int a, int b, int c) 22 { 23 int ans=0; 24 int i=0; 25 if (a < b && a < c) 26 { 27 i = a; 28 } 29 else if (b < a && b < c) 30 { 31 i = b; 32 } 33 else 34 { 35 i = c; 36 } 37 for (i; i > 0; i--) 38 { 39 if (a % i == 0 && b % i == 0 && c % i == 0) 40 { 41 ans = i; 42 break; 43 } 44 } 45 return ans; 46 }

实 验 7
1 #include <stdio.h> 2 #include <stdlib.h> 3 int print_charman(int n); 4 int main() 5 { 6 int n; 7 printf("Enter n: "); 8 scanf_s("%d", &n); 9 print_charman(n); 10 return 0; 11 } 12 int print_charman(int n) 13 { 14 int t = 2 * n - 1; 15 for (t; t > 0; t -= 2) 16 { 17 for (int i = (2 * n - 1 - t) / 2; i > 0; i--) 18 { 19 printf("\t"); 20 } 21 for (int i = t; i > 0; i--) 22 { 23 printf(" O \t"); 24 } 25 printf("\n"); 26 for (int i = (2 * n - 1 - t) / 2; i > 0; i--) 27 { 28 printf("\t"); 29 } 30 for (int i = t; i > 0; i--) 31 { 32 printf("<H>\t"); 33 } 34 printf("\n"); 35 for (int i = (2 * n - 1 - t) / 2; i > 0; i--) 36 { 37 printf("\t"); 38 } 39 for (int i = t; i > 0; i--) 40 { 41 printf("I I\t"); 42 } 43 printf("\n"); 44 } 45 }


                    
                
                
            
        
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