实验三

task-1

#include<stdio.h>
#include<stdlib.h>
#include<time.h>
#include<unistd.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(1);
    }

    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);
}

每隔一秒在屏幕上打印出1个随机位置的"hi, May~"，共十个

task-2.1

#include <stdio.h>
#include<stdlib.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));
    system("pause");

return 0;
}
long long fac(int n)
{
    static long long p = 1;

    printf("p=%11d\n",p);
    p = p * n;
    return p;
}

task-2.2

#include <stdio.h>
#include<stdlib.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);
    system("pause");
    return 0;
}

int func(int a, int b)
{
    static int m = 0, i = 2;
    i += m + 1;
    m = i + a + b;

    return m;
}

static变量即可用作静态局部变量又可用作静态全局变量。

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>
#include<stdlib.h>
int i;
void hanoi(unsigned n,char from,char to,char temp);
void move(unsigned n,char from,char to);
int main()
{   
    unsigned n;
    while(scanf("%u",&n)!=EOF)
    {    i=0;
        hanoi(n,'A','C','B');
    printf("一共移动了%d次",i);}

    system("pause");
}
void hanoi(unsigned n,char from,char to,char temp)
{ if(n==1)
   move(n,from,to);
else
    {
    hanoi(n-1,from,temp,to);
    move(n,from,to);
    hanoi(n-1,temp,to,from);}


}
void move (unsigned n,char from,char to)
{    i++;
    printf("%u:%c-->%c\n",n,from,to);

}

task-5

#include<stdio.h>
#include<stdlib.h>
#include<math.h>
int is_prime(int n);
int main()
{
    int n,p,q,flagp,flagq;              
    for(n=4;n<=20;n+=2)
    {
        p = 1;
        do
        {
            p++;
            q=n-p;
            flagp=is_prime(p);
            flagq=is_prime(q);
        } 
        while(flagq*flagp == 0);
        printf("%d =%d + %d\n", n, p, q);
    }
    return 0;
}
int is_prime(int n)
{
    int k;
    for(k=2;k<=sqrt(n);k++)
        if(n%k==0)
        {
            return 0;
        }
        return 1;
        
}

task-6

#include<stdio.h>
#include<stdlib.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:");

    }


    system("pause");
}
long fun(long s)
{    long i,p,t=0,x=0,m;
    p=s;
    while(p!=0)
   {        
    i=p%10;
    if(i%2==1)
    t=t*10+i;
     p/=10;
   }
    while(t!=0)
  {    m=t%10;
    x=x*10+m;
    t/=10;
  }

    return x;


}