实验三

#include<stdio.h> 
int main()
{
    double a,s,t m=0;
        int b,n;
        printf("输入n和a:");
        scanf("%d%lf",&n,&a);
    for(b=1,a=0;b<=n;b=b+1)
   {
  
    m=a+m*10;
    t=b/m;
    }
  printf("a的值为%lf\n",a);
  return 0;  

}

#include<stdio.h>
#include<math.h> 
int main()
{
    long int a;
    int t,i,n;
    t=0;
    n=1;
    printf("Enter a number:");
    scanf("%ld",&a);
    while(a>0)
    {
        i=a%10;
        a=a/10;
        if(i%2!=0)
        {
            t=t+i*n;
            n=n*10;
            
        }
    }
    printf("New number is :%d\n",t);
    return 0;
    
    
}

#include<math.h>
#include<stdio.h>
#include<stdlib.h>
int math(){
    float a,b,c,x1,x2;
    float delta,real,imag;
    printf("Enter a,b,c:");
    while(scanf("%f%f%f",&a,&b,&c)){
        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);
            
        }
    }
    printf("Enter a,b,c:\n");
    
}
system("pause");
return 0;
}

#include<stdio.h>
#include<stdlib.h>
#include<time.h>
int main(){
    int guessNumber;
    int ans;
    srand((time(0)));
    guessNumber=1+rand()%100;
    do{
        printf("your guess number is (1~100):");
        scanf("%d",&ans);
        if(ans<guessNumber)
        printf("%d is lower than the number.\n",ans);
        else if(ans>guessNumber)
        printf("%d higher then the number.\n",ans);
    }while(ans!=guessNumber);
    printf("Congratulations.you hit it~\n");
    system("pause");
    return 0;
    
    
}

#include<stdio.h>
#include<stdlib.h>
int main(){
    int number,max,min,n;
    n=1;
    printf("输入第%d个数:",n);
    scanf("%d",&number);
    max=number;
    min=number;
    while(n<=4){
        n++;
        printf("输入第%d个数:",n);
        scanf("%d",&number);
        if(max<=number)
        max=number;
        else if(min>=number);
        min=number;
    }
    printf("最大数为：%d\n",max);
    printf("最小数为：%d\n",min);
    system("pause");
    return 0;
}

#include<stdio.h>
#include<math.h>
int isprime(int n);
int main(){
    int i;
    for(i=101;i<=200;i++)
    {
        if(isprime(i))
        printf("%4d",i);
    
    }
    return 0;

        
    
}
int isprime(int n)
{
    int k;
    for(k=2;k<=sqrt(n);k++)
    if(n%k==0)
    return 0;
    return 1;
}