实验3

#include<stdio.h>
#include<stdlib.h>
    long long fac(int n);
//利用局部变量static的特性，计算阶乘
int main(){
    int i,n;
    printf("Enter n:");
    scanf("%d",&n);

    for(i=1;i<=n;++i){
        printf("%d!=%11d\n",i,fac(i));
    }
    system("pause");
        return 0;
    }
    long long fac(int n)
    {
        static long long p=1;
        p=p*n;
        return p;
    }

 

 

#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);
}

 

 总结：static变量只在最初赋值一次，后面再通过static赋值时变量值不变

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

    }
    system("pause");
    return 0;
}
void printSymbol(int n,char symbol){
    int a=1;
    for(a=1;a<=n;a++){
        printf("%c",symbol);
    }}

 

 

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

    }
    system("pause");
    return 0;
}
void printSymbol(int n,char symbol){
    int a=1;
    if(n==1)
        printf("%c",symbol);
    else {printf("%c",symbol);
    printSymbol(n-1,symbol);}
}

 

 

#include<stdio.h>
#include<stdlib.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=%11d\n",n,f);
    }



    system("pause");
    return 0;}
long long fun(int n){
    long a=1;
    if(n==1)
        a=1;
    else a=2*fun(n-1)+1;
    return a;}

 

 

#include<stdio.h>
#include<stdlib.h>
int isPrime(int a);
int main(){
    int a,b;
    a=0;

for(b=101;b<=200;b++){
    if(isPrime(b)==1)
        {printf("%4d",b);
    a++;}
}
printf("\n素数有%d个",a);
system("pause");
return 0;
}
int isPrime(int a){
    int b;
    for(b=2;b<=15;b++){
    if(a%b==0){a=1;break;}
    }
    return a;}

 

#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,b,c,d;
    d=1;
    b=0;
    for(a=1;(s/a)>=1;a=a*10)
    {

        if((s/a)%2==1){
            b=b+d*((s/a)%10);
        
            d=d*10;
        }
    }
    return b;
}

 

 

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

return 0; 
}

double fun(int n)
{
    int a,b,c,e;
    double d,ans;
    ans=0.0;
    b=1;
    e=1;
    for(a=1;a<=n;a++){
        c=1;
        for(b=1;b<=a;b++){
            
            c=c*b;
    
        }
        d=1.0*e/c;
        e=-e;
        ans=ans+d;
    }
    return ans;
}