实验三
task1
#include <stdio.h> #include <stdlib.h> #include <time.h> #include <windows.h> #define N 80 void printText(int line, int col, char text[]); // 函数声明 void printSpaces(int n); // 函数声明 void printBlankLines(int n); // 函数声明 int main() { int line, col, i; char text[N] = "hi, May~"; srand(time(0)); // 以当前系统时间作为随机种子 for (i = 1; i <= 10; ++i) { line = rand() % 25; col = rand() % 80; printText(line, col, text); Sleep(1000); // 暂停1000ms } return 0; } // 打印n个空格 void printSpaces(int n) { int i; for (i = 1; i <= n; ++i) printf(" "); } // 打印n行空白行 void printBlankLines(int n) { int i; for (i = 1; i <= n; ++i) printf("\n"); } // 在第line行第col列打印一段文本 void printText(int line, int col, char text[]) { printBlankLines(line - 1); // 打印n-1行空行 printSpaces(col - 1); // 打印n-1列空格 printf("%s", text); }
功能:实现在第line行第col列输出hi,May~,一共输出十次。
task2-1
#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("%di!=%lld\n", i, fac(i)); return 0; } long long fac(int n) { static long long p = 1; p = p * n; return p; }
task2-2
#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; }
运行结果与我预期的相同。
局部static的特性:在一次程序运行中,变量的值随着每次计算发生改变,不变回初始值。
task3
#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 result; if (n == 0) result = 0; else if (n >= 1 || n <= 32) result = 2 * fun(n - 1) + 1; return result; }
task 4
#define _CRT_SECURE_NO_WARNINGS #include<stdio.h> void hanoi(unsigned int n, char from, char temp, char to); void moveplate(unsigned int n, char from, char to); int cs; int main() { unsigned int n; while (scanf("%u", &n) != EOF) { getchar(); hanoi(n, 'A', 'B', 'C'); printf("次数时:%d", cs); cs = 0; printf("\n\n"); } 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("%u:%c-->%c\n", n, from, to); cs++; }
task5
#define _CRT_SECURE_NO_WARNINGS #include<stdio.h> int is_prime(int n); int is_prime(int n) { int i; if (n == 1) return 0; if (n > 1) { for (i = 2; i < n; i++) if (n % i == 0) return 0; if (i = n - 1) return 1; } } int main() { int n,i; for (n = 4; n <= 20; n++) { if (n % 2 == 0) { for (i = 2; i < n - 1; i++) if (is_prime(i) && is_prime(n - i)) { printf("%d=%d+%d\n", n, i, n - i); break; } } } return 0; }
task6
#define _CRT_SECURE_NO_WARNINGS #include <stdio.h> #define N 80 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 t = 0,h=0,m; long ys; while (s > 0) { ys = s % 10; if (ys % 2 != 0) t = t * 10 + ys; s = s / 10; } while (t > 0) { m = t % 10; h = h * 10+m; t = t / 10; } return h; }
收获:1.static的用法
2.全局变量的使用
3.task6,使用数组反而更麻烦。