实验三
Task 1
#define _CRT_SECURE_NO_WARNINGS #include<stdio.h> #include<stdlib.h> #include<time.h> #include<windows.h> #define N 80 void printText(int line, int col, char text[]); void printSpaces(int n); void printBlanklines(int n); int main() { int line, col, i; char text[N] = "hi,May~"; srand(time(0)); for (i = 1; i <= 10; ++i) { line = rand() % 25; col = rand() % 80; printText(line, col, text); Sleep(1000); } return 0; } void printSpaces(int n) { int i; for (i = 1; i <= n; i++) printf(" "); } void printBlanklines(int n) { int i; for (i = 1; i <= n; i++) printf("\n"); } void printText(int line, int col, char text[]) { printBlanklines(line - 1); printSpaces(col - 1); printf("%s", text); }
功能:每隔一秒在随机的行和列打印一个“hi,May~"
Task 2.1
#define _CRT_SECURE_NO_WARNINGS #include <stdio.h> long long fac(int n); int main() { int i, n; printf("Enter n: "); scanf("%d", &n); for (i = 1; i <= n; ++i) { printf("%d! = %lld\n", i, fac(i)); } return 0; } long long fac(int n) { static long long p = 1; printf("p=%lld\n", p); p = p * n; return p; }
总结:"static long long p = 1"只起效一次,之后函数调用时采用上一次运算所得值运算。
Task 2.2
#define _CRT_SECURE_NO_WARNINGS #include <stdio.h> int func(int, int); int main() { int k = 4, m = 1, p1, p2; p1 = func(k, m); p2 = func(k, m); printf("%d,%d\n", p1, p2); return 0; } int func(int a, int b) { static int m = 0, i = 2; i += m + 1; m = i + a + b; return m; }
理论计算p1=8,p2=17。运行结果符合计算。
Task 3
#define _CRT_SECURE_NO_WARNINGS #include<stdio.h> long long fun(int n); int main() { int n; long long f; while (scanf("%d", &n) != EOF) { f = fun(n); printf("n =%d, f=%lld\n", n, f); } return 0; } long long fun(int n) { long long k; if (n == 0) { return 0; } else { k = 2 * fun(n - 1) + 1; } return k; }
Task 4
#define _CRT_SECURE_NO_WARNINGS #include<stdio.h> #include<math.h> void hanoi(unsigned int n, char from, char temp, char to); void moveplate(unsigned int n, char from, char to); int main() { unsigned int n; long long t; while (scanf("%u", &n) != EOF) { hanoi(n, 'A', 'B', 'C'); t = pow(2, n) - 1; printf("\n一共移动了%d次.\n\n", t); } return 0; } void hanoi(unsigned int n, char from, char temp, char to) { if (n == 1) moveplate(n, from, to); else { hanoi(n - 1, from, to, temp); moveplate(n, from, to); hanoi(n - 1, temp, from, to); } } void moveplate(unsigned int n, char from, char to) { printf("第%u个盘子:%c-->%c\n", n, from, to); }
Task 5
#define _CRT_SECURE_NO_WARNINGS #include<stdio.h> #include<math.h> #include<stdlib.h> int is_prime(int n); int main() { int i, j; for (i = 4; i <= 20; i += 2) { for (j = 2; j <= i / 2; j++) { if (is_prime(j) == 1 && is_prime(i - j) == 1) { printf("%d=%d+%d\n", i, j, (i - j)); } } } return 0; } int is_prime(int n) { int i; for (i = 2; i <= sqrt(n); i++) { if (n % i == 0) break; } if (i > sqrt(n) && n > 1) { return 1; } else { return 0; } }
Task 6
#define _CRT_SECURE_NO_WARNINGS #include<stdio.h> #include<math.h> long fun(long s); int main() { long s, t; printf("Enter a number:"); while (scanf("%ld", &s) != EOF) { t = fun(s); printf("new number is: %ld\n\n", t); printf("Enter a number:"); } return 0; } long fun(long s) { int i, k, ans = 0; for (i = 0; s != 0; s = s / 10) { k = s % 10; if (k % 2 != 0) { ans = ans + k * pow(10, i); i++; } } return ans; }