实验4

#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)/(2*a);
            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;
     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);
}

#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 i=0;
     long long k=1;
    while(i<n){
        i++;
        k=k*2.0;    
    }
    k = k-1;
    return k;
    }

#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){
for(int a=1;a<=n;a++)
{
        int b=n-a;
        for(int i=1;i<=b;i++)
        {
            printf(" ");}
        int m = 2*a-1;
        for(int t = 1;t<=m;t++)
        {
            printf("%c", symbol);}
            printf("\n");
        }

    }