实验4

#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;
}

#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);
}

static变量使变量在该函数中保持之前的值不变且不能被其他函数使用、

#include <stdio.h>
#define N 1000
int fun(int n,int m,int bb[N]) {
    int i,j,k=0,flag;
    
    for(j=n;j<=m;j++) {
          flag=1;   
        for(i=2;i<j;i++)
            if(j%i==0) {  
               flag=0;
               break;
        }
        if(flag==1) 
           bb[k++]=j;
    }
    return k;
}

int main(){
    int n=0,m=0,i,k,bb[N];
    
    scanf("%d",&n);
    scanf("%d",&m);
    
    for(i=0;i<m-n;i++)
        bb[i]=0;
        
    k=fun(n,m,bb); 
    
    for(i=0;i<k;i++)
        printf("%4d",bb[i]);
        
    return 0;
}

#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;
    
    if(n==1)
    sum=1;

    if(n>1)
    sum=2*fun(n-1)+1;
    
    return sum;
}

#include <stdio.h> 
int main() {
    int n, symbol;
    
    while(scanf("%d %c", &n, &symbol) != EOF) {
        draw(n, symbol); 
        
        printf("\n");
    }
    
    return 0;
} 
void draw(int n,char symbol)
{
    int i,j,t,p,q;
    
    if(n==1)
    printf("%c",symbol);
    
    for(i=1;i<=n;i++)
    {
        q=0;
        p=2*i-1;
        for(t=1;t<=n-i;t++)
            printf(" ");
        for(j=1;j<=p;j++)
     {
        printf("%c",symbol);
        q++;
        if(q==p){
        printf("\n");
                } 
     }
    }
  
}