实验3

实验任务1

#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;
18　　　printf("p = %lld\n", p); 
    return p;
20     }

 

#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;
}

 局部static变量的特性：分配静态内存，当函数调用完成后，内存不回收。

实验任务2

//迭代
#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);
}

 

//递归
#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!=0){
        printf("%c",symbol);
        return printSymbol (n-1,symbol);
    }    
    
}

 第一种好点，更直观，只调用了一次，但第二种解决复杂点的问题可能有奇效，各有优劣。

实验任务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){
    if(n==1)
        return 1;
    else 
        return 2*(fun(n-1)+1)-1;
}

 

实验任务4

#include<stdio.h>
#include<math.h>
int isPrime(int n){
    int i;
    for(i = 2;i<=sqrt(n);i++)
        if(n%i==0)
            return 0;
    return 1;    
    
}
int main(){
    int i;
    int num  = 0 ;
    int k =0;
    for(i=101;i<=200;i++){
    
        if (isPrime(i) == 0){
        
            printf("%d ",i);
            num++;
            k++;}
        if(k==10){
            printf("\n");
            k = 0;
        }        
}
    printf("\n一共有%d个非素数",num);
}

 实验任务5

#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){
    int i=1;
    int t;
    int num=0;
    while(s!=0){
        t = s%10;
        if (t % 2 ==1){
        num = num + t*i;
        i *=10;
        }
        s = s/10;
    }
    return num;
}

 实验任务6

#include <stdio.h>
#include <math.h>
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){
    double qwq=1;
    int i;
    double s =0;
    
    for(i=1;i<=n;i++){
            qwq = qwq * i;        
    s= s+pow(-1,i-1)*(1/qwq);}
return s;
}

 总结

万事收工