实验3

#include <stdio.h>
#include <stdlib.h>
#include <time.h>
#define N 5
int main() {
    int x, n;
    srand(time(0)); // 以当前系统时间作为随机种子
    for (n = 1; n <= N; n++) {
        x = rand() % 100; // 生成一个0~99之间的随机整数
        printf("%3d", x);
    }
    printf("\n");
    return 0;
}

 

 

# define _CRT_SECURE_NO_DEPRECATE
#include <stdio.h>
#include <stdlib.h>
#include <time.h>
#define N 1
int main() {
    int x, n, i = 0;
    srand(time(0));
    x = 1+rand() % 30;
    printf("猜猜2021年5月哪天是你的lucky day\n");
    printf("开始喽，你有三次机会，猜吧（1~31）\n");
    for (i = 1; i <= 3; i++)
    {
        scanf("%d", &n);
        
        if (n > x)
            printf("你猜的日期晚啦，luck day悄悄溜到前面啦\n");
        else if (n < x)
            printf("你猜的日期早了，luck day还没到呢\n");
        else
            printf("luck day\n");
        printf("再一次\n");
    }
    if (i > 3)
        printf("次数用完啦，偷偷告诉你：你的luck day是%d号\n",x);
    return 0;
}

 

 

#include<stdio.h>
#define _CRT_SECURE_NO_DEPRECATE
int main()
{
    long x, y, m, n;
    while (printf("Enter your number : "), scanf("%ld", &x) != EOF)
    {
        m = x;
        n = 1;
        while (m = m/10)
            n = n*10;
        while (x)
        {
            if ((y = x / n) % 2 != 0)
                (m *= 10) += y;
            x %= n;
            n /= 10;
        }
        printf("New number is:%ld\n", m);
    }
    return 0;
}

 

 

#include <math.h>
#include <stdio.h>
#define _CRT_SECURE_NO_DEPRECATE
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 = %.2f, x2 = %.2f\n", 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>
#define _CRT_SECURE_NO_DEPRECATE
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;
}
double fun(int n) {
    if (n == 1)
        return 1;
    else if (n == 2)
        return 0.5;
    else
        return fun(n - 1) - (fun(n - 1)) / n + (fun(n - 2)) / n;
    
}

 

 

#include <stdio.h>
#include <math.h>
int isPrime(int n); 
int main(){
    int n,i,m,a,t=0;
    printf("获得两数之间的素数\n请输入两数：\n"); 
    scanf("%d%d",&i,&n);
    a=i;
    for(;i<=n;i++){
        m=isPrime(i);
        if(m!=0&&m!=1){
        printf("%d ",m); 
        t=t+1;
        if(t%5==0)
        printf("\n");}}
    printf("\n\n%d^%d之间素数个数为：%d",a,n,t);
    return 0;
}

int isPrime(int n){
    int x,result;
    int y=2;
    x=sqrt(n);
    while(y<=x&&n%y!=0){
        y=y+1;
    }
    if(y>x)
    return n;
    else
    return 0;
}