实验四

#include<math.h> 
#include<stdio.h> 
void solve(double a,double b,double c);
int main(){
    double a,b,c;
    printf("Enter a,b,c:");
    while(scanf("%lf%lf%lf",&a,&b,&c)!=EOF){
        solve(a,b,c);
        printf("Enter a,b,c:");
    } 
    return 0;
}
void solve(double a,double b,double c){
    double x1,x2;
    double delta,real,imag;
    if(a==0)
      printf("not quadratic equation.\n");
    else{
        delta=b*b-4*a*c;
        if(delta>=0){
            x1=(-b+sqrt(delta))/(2*a);
            x2=(-b-sqrt(delta))/(2*a);
            printf("x1=%f,x2=%f\n",x1,x2);
        }
        else{
            real=-b/(2*a);
            imag=sqrt(-delta);
            printf("x1=%f+%fi,x2=%f-%fi\n",real,imag,real,imag);
        }
    }
}

 

#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>
int fun(int,int);
int main(){
    int k=4,m=1,p1,p2;
    p1=fun(k,m);
    p2=fun(k,m);
    printf("%d,%d\n",p1,p2);
    return 0;
}
int fun(int a,int b){
    static int m=0,i=2;
    i+=m+1;
    m=i+a+b;
    return (m);
}

 

#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)
          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 i;
    long long int result,t=1;
    for(i=1;i<=n;i++)
    t*=2;
    result=t-1;
    
    return result;
}

#include<stdio.h>
void draw(int n,char symbol);
#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 t,line;
    for(line=1;line<n+1;line++){
    
        for(t=0;t<n-line;t++) 
            printf(" ");
        for(t=0;t<2*line-1;t++)
            printf("%c",symbol);
         printf("\n");
         }
    }