实验三

#include<stdio.h>
#include<stdlib.h>
#include<time.h>
#define   N  5
int main(){
    int x,n; 
     
     srand(time(0)); 
     for(n=1;n<=N;n++){
   x=rand()%100; 
    printf("%3d",x); 
	 }
printf("\n");
return 0;


} 

　　

　　

 

 

#include<stdio.h>
#include<stdlib.h>
#include<time.h>
#define N 3
int main(){
	int x,n,x1,x2,x3;
	srand(time(0));
		x=1+rand()%31;
		
	for(n=1;n<=N;n++){
	
	
	printf("猜猜2021年五月哪一天是你的幸运日\n");
	printf("你有三次机会，猜吧(1-31)"); 
	scanf("%d",&x1) ;
	if(x1==x)
	
	{
	printf("恭喜你猜对了");break;}
	else if(x1>x)
	printf("你猜的日期晚了，luck day悄悄跑到前面去了\n");
	else 
	printf("你猜的日期早了,luck day还没到呢\n");

	 
	 
	 	scanf("%d",&x2) ;
	if(x2==x){
	
	printf("恭喜你猜对了");break;}
	else{
	
	if(x2>x)
	
	printf("你猜的日期晚了，luck day悄悄跑到前面去了\n") ;
	else
	printf("你猜的日期早了,luck day还没到呢\n");
}
 	scanf("%d",&x3) ;
	if(x3==x){
	
	printf("恭喜你猜对了");break;}
	else{
	
	if(x3>x)
	
	printf("你猜的日期晚了，luck day悄悄跑到前面去了\n") ;
	else
	printf("你猜的日期早了,luck day还没到呢\n");
}
printf("悄悄告诉你，没有机会了，luck day是%d", x);
return 0;
}}

　　

 

 

#include<stdio.h> 
#include<stdlib.h>

int main(){
int a, c=1;
long int b, s=0;
    
    
    printf("输入一个数字；");
    scanf("%d",&a);
   
    do{
    a=a/10;
    
    b=a%10;
    if(b%2！=0){
    
    s=s+b*c;
    c=c*10;
    }
    eles
    s=s 

}
    while(n!=0);
    printf("新的数字是；%d"，s);
    return 0; 

}

#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("%if%if%if",&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=%.2f x2=%.2f",x1,x2);
            
        }
        else{
            real=-b/(2*a);
            imag=sqrt(-delta)/(2*a);
            printf("x1=%.2f + %.2fi,x2=%.2f- %.2fi\n",real,imag,real,imag);
        }
    }
}

 

 

 

 

#include <stdio.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;
}

// 函数定义 
double fun(int n) {
    int x,c;
    double sum=0;
    double y;
    y=1;
    c=2;
    for(x=1;x<=n;x++){
        sum=sum+1/y;
        y=(-1)*y*(c);
        c=c+1;
    }

    return sum;
}

　　

 

 

 

#include<stdio.h>
#include<stdlib.h>
int isPrime(int);
int main(){
    int i=0,x,s,sum=0;
    for(x=101;x<=200;x++){
        s=isPrime(x);
        if(s==0){
            printf(" %d",x);
            i++;
            x++;
            sum++;
            if(sum%5==0)
            {
                printf(" \n");
            }
        }
    }
    printf("\n101~200之间素数一共有%d个\n",i);
    system("pause");
    return 0;
}
int isPrime (int x)
{
    int n=0,i;
    for(i=2;i<x;i++){
        if(x%i==0)
            n++;
    }return n;
}