实验三捏
Task 1
#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)); /*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); }
以弹幕的形式打印hi,may
Task 2-1
/*利用局部static变量的特性,计算阶乘*/ #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;/*静态局部变量*/ printf("p = %lld\n", p); p = p * n; return p; }
Task 2-2
#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; }
结果相同。
局部static变量特性为,只初始化一次。
Task 3
#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) { int i; long long a=0,p=1; if(n==0) a=1; else { for(i=1;i<=n;i++) { p=p*2; } a=p-1; } return a; }
Task 4
#include <stdio.h> void hanoi(unsigned int n,char from,char temp,char to);/*递归函数*/ void moveplate(unsigned int n,char from,char to);/*移动函数*/ int main() { unsigned int n; extern int a; while(scanf("%u",&n)!=EOF) /*盘子个数*/ { hanoi(n,'A','B','C'); printf("次数为%d\n",a); printf("\n"); a=0; } return 0; } int a=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);/*n-1个盘子从A以C为中转移到B*/ moveplate(n,from,to);/*将盘子n从A移到C*/ hanoi(n-1,temp,from,to);/*将n-1个盘子从B以A为中转移到C*/ } } void moveplate(unsigned int n,char from,char to) { printf("%u:%c-->%c\n",n,from,to); a++; }
Task 5
#include <stdio.h> #include <math.h> int is_prime(int n); int main() { int n,a1,a2,b; for(n=4;n<=20;n++) { if(n%2==0) { for(b=2;b<=n/2;b++) { a1=is_prime(b); a2=is_prime(n-b); if(a1==1&&a2==1) { printf("%d=%d+%d\n",n,b,n-b); break; } } } } return 0; } int is_prime(int n) { int i,m,b=0; m=sqrt(n); for(i=2;i<=m;i++) { if(n%i==0) { b=0; break; } } if(i>m) b=1; return b; }
Task 6
#include <stdio.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) { long a=0,b=0,n=1,i,c=1; while(s!=0) { a=s%10; if(a%2!=0) { b=a; s=s/10; break; } s=s/10; } while(s!=0) { a=s%10; if(a%2!=0) { for(i=1;i<=n;i++) { a=a*10; } b=b+a; n++; } s=s/10; } return b; }