实验三

task1.

#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;
    p = p * n;
    return p;
}

　　

 

#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;
}

　　

 

task2.

#include<stdio.h>

void printSymbol(int n,char symbol);

int main()
{
    int n;
    char symbol;
    
    while( scanf("%d %c",&n,&symbol)!=EOF)
    {
        printSymbol(n,symbol);
        printf("\n");
    }
    
    return 0;
}

void printSymbol(int n,char symbol)
{
    int i;
    
    for(i=0;i<n;i++)
    printf("%c",symbol);
}

　　

 

 

 

 

#include<stdio.h>

void printSymbol(int n,char symbol);

int main()
{
    int n;
    char symbol;
    
    while( scanf("%d %c",&n,&symbol)!=EOF)
    {
        printSymbol(n,symbol);
        printf("\n");
    }
    
    return 0;
}

void printSymbol(int n,char symbol)
{
    if(n==1)
    printf("%c",symbol);
    else
    {
        printSymbol(n-1,symbol);
        printf("%c",symbol);
    }
}

　　

 

 

 task3.

#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 sum,f,a;
    sum=1;
    for(a=1;a<=n;a++){
        sum=sum*2;
    }
    f=sum-1;
    
}

　　

 

 task4.

#include <stdio.h>
#include <math.h>
int isPrime(int n);
int main()
{
    int a,n,i=0;
    for(n=101;n<=200;n++)
    {
        if(isPrime(n)==0)
        {
            printf("%8d",n);
            i++;
        }       
    }
    printf("\n");
    printf("101~200之间一共有%d个非素数",i);
    return 0;
}

int isPrime(int n)
{
    int p;
    for(p=2;p<=n;p++)
    {
        if(n%p==0)
        break;
      }
       if(p<n)    
        {
            return 0;
        }
        else
        {
             return 1;
        }    
}

　　

 

 

task5.

#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 m=0;
    long n=0,p=1;
    while(s>0)
    {
        m=s%10;
        if(m%2!=0)
        {
            n = n+m*p;
            p=p*10;
        }
        s=s/10;
    }
    return n;
}

　　

 

 task6.

#include <stdio.h>
#pragma warning (disable:4996)
double fun(int n);
 int main() {
     int n; double s;
     printf("Enter n(1~10): ");
     while (scanf("%d", &n) != EOF) { s = fun(n);
    printf("n = %d, s= %f\n\n", n, s);
    printf("Enter n(1~10): "); 
     }
     return 0; 
}

 double fun(int n) {
     int  p;
     double    sum;
     p = 1;
     sum = 0;
         for (int i = 1;i <= n;i++) {
             p = p * -1 * i;
             sum = sum + 1 / (double)p * -1;
         }
         return sum;
 }