第三次实验作业

1.

//一元二次方程求解
//重复执行,直到按Ctrl+Z结束
//
#include <math.h>
#include <stdio.h>

int main(){
    float a,b,c,x1,x2;
    float delta, real, imag;
    
    printf("Enter a,b,c: ");
    
    while(scanf("%f%f%f", &a, &b, &c) !=EOF) {
        if(a == 0)
            printf("not quadratic equation.\n\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\n",x1,x2);
            }
            else {
                real = -b/(2*a);
                imag = sqrt(-delta)/(2*a);
                printf("x1 = %.2f+ %.2fi, x2 =%.2f-%.2fi\n\n",real,imag,real,imag);
            }
        }
        
        printf("Enter a,b,c :");     
    }
    
    return 0;
} 

 

 

2.

//生成N个0~9之间的随机整数,并打印输出
#include <stdio.h>
#include <stdlib.h>
#include <time.h>
#define N 5

int main(){
    int x, n;
    
    srand(time(0));
    n = 0;
    do {
        n++;
        x = rand()%10;
        printf("%3d",x);
    }while(n<N);
    
    printf("\n");
    
    return 0;
} 

 

 

3.

#include <stdio.h>
#include <math.h>
int main(){
    int i,m,n,count;
    count=0;
    
    
    for (m=101;m<=200;m++){
        n=sqrt(m);
        for(i=2;i<=n;i++){
            if(m%i==0)break;
        }
        
        if(i>n){
            printf("%6d",m);
            count++;
            if (count%5==0)
            printf("\n"); 
        }
    }
    printf("\n101~200间有%d个素数.",count);
    return 0;
} 

 

4.

#include<stdio.h>
#include<math.h>
int main(){
    long x,y,z;
    while (printf("enter a biiiiiiiig number :"),scanf("%ld",&x)!=EOF){
        long i=0,z=0;
        while (x>0){
            y=x%10;
            if(y%2!=0){
                z+=y*pow(10,i);
                i++; 
            }
            x=x/10;
        }
        printf("neeeeeeeew number is:%ld\n",z);
        
    }
    return 0;
} 

 

 

5.

#include <stdio.h>
#include <math.h>
int main(){
    int m,n;
    float s;
    printf("Enter n(1~10):");
    while(scanf("%d",&n)!=EOF){
        float s=0,i=1;
        for(m=1;m<=n;m++){
            i=i*m;
            s=s+pow(-1,m-1)*(1/i);
        }
        printf("n=%d,s=%f\n",n,s);
        printf("Enter n(1~10):");
    }
    return 0;
} 

 

6.

#include <stdio.h>
#include <stdlib.h>
#include <time.h>
int main(){
    int data,answer,count;
    srand((unsigned)time(NULL));
    data= rand()% 31;
    printf("guess guess 2020年哪一天会是你的lucky day\n");
    printf("开始喽,你居然有三次机会!猜吧 (1~31):");
    
    while (count<3) {
        scanf("%d",&answer);
        if(data==answer) {
            printf("这就对了?\n");break;}
        
        else if(data>answer){
            printf("猜的也太小气了吧!?\n");
        }
        else{
        
        printf("猜的也太大气了吧!?\n");}
        count++;
    }
    if(count>=3)
    printf("你无了,回复TD退订\n");
    return 0;
    } 

 

posted @ 2020-11-19 23:51  小雨。。。  阅读(102)  评论(1编辑  收藏  举报