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;
    
}