实验2 C语言控制语句应用编程

1.

#include <stdio.h>
#include <stdlib.h> 
#include <time.h> 
#define N 5 
int main() 
{ 
int grade, number; 
int i; 
srand(time(0)); // 以当前系统时间作为随机种子 
for(i=0; i<N; ++i) 
{ 
grade = rand()%4 + 2018;
number = rand()%999 + 1;
printf("%d8330%04d\n", grade, number);
}
return 0; 
}

问题1：产生2018到2021的随机数并赋值给grade；

问题2：产生1到999的随机数并赋值给number；

问题3：输出N个随机的学号，其中学号前四位为2018到2021的随机数，表示年级；后三位为1到999的随机数。

 

2.

#include <stdio.h>
#include <stdlib.h> 
#include <time.h> 
int main()
{
    int d,ld,i=3; 
    printf("猜猜2022年4月哪一天是你的幸运日\n开始喽，你有三次机会，猜吧（1-30）:");
    srand(time(0));
    ld=rand()%30+1;
    while(i)
    {
    scanf("%d",&d);    
    if(d==ld)
        {
        printf("哇，猜中了");
        break;
        }
    if(d<ld)
        {
        printf("你猜的日期早了，你的lucky day还没到呢\n");
        i--;
        }
    if(d>ld) 
        {
        printf("你猜的日期晚了，你的lucky day已经过啦\n");    
        i--;
        }    
    }
    if(i==0) printf("次数用完啦，偷偷告诉你，4月，你的lucky day是%d号",ld);
    return 0;
}

3.

#include<stdio.h>
int main()
{
    char color;
    while(scanf("%c",&color)!=EOF)
    {
    if(color=='r') printf("stop!\n");
    else if(color=='g') printf("go go go\n");
    else if(color=='y') printf("wait a sec\n");
    else printf("sth must be wrong\n");
    scanf("%c",&color);
    }
    return 0;
}

4.

#include<stdio.h>
double compute_s(int n,int a);
int main()
{     
    int n,a;
    while(scanf("%d%d",&n,&a)!=EOF)
    printf("n=%d,a=%d,s=%lf\n",n,a,compute_s(n,a));
    return 0;
}
double compute_s(int n,int a)
{    
    double s=0.0,under=0.0;
    for(int i=1;i<=n;i++)
    {    under=a+under*10;
        s+=i/under;
    }
    return s;
}

5.

#include<stdio.h>
void scan_formula(int a,int b);
int main()
{
    int i,j;
    for(i=1;i<=9;i++)
    {    
        for(j=1;j<=i;j++) scan_formula(j,i);
        printf("\n");
    }
    return 0;
}
void scan_formula(int a,int b)
{
    printf("%d×%d=%d ",a,b,a*b);
}

6.1

#include<stdio.h>
void print_vertical_guys(int a);
int main()
{    
    int n;
    printf("input n:");
    scanf("%d",&n);
    print_vertical_guys(n);
    return 0;
}
void print_vertical_guys(int a)
{
    for(int i=1;i<=a;i++) printf(" O\n<H>\nI I\n");
}

 

6.2

#include<stdio.h>
void print_horizontal_guys(int b);
int main()
{    
    int n;
    printf("input n:");
    scanf("%d",&n);
    print_horizontal_guys(n);    
    return 0;
}
void print_horizontal_guys(int b)
{    
    char guy[3][10]={" O ","<H>","I I"};
    for(int i=0;i<3;i++) 
    {
        for(int j=1;j<=b;j++) printf("%s    ",guy[i]);    
        printf("\n");
    }
}

 

6.3

#include<stdio.h>
void print_horizontal_guys_with_gaps(int c,int d);
int main()
{
    int n;
    printf("input n:");
    scanf("%d",&n);
    for(int i=2*n-1;i>=1;i-=2) print_horizontal_guys_with_gaps(i,n);
    return 0;
}
void print_horizontal_guys_with_gaps(int c,int d)
{    
    char guy[3][10]={" O ","<H>","I I"};
    for(int i=0;i<3;i++) 
    {
        for(int k=(2*d-1-c)/2;k>0;k--) printf("       ");
        for(int j=1;j<=c;j++) printf("%s    ",guy[i]);
        for(int k=(2*d-1-c)/2;k>0;k--) printf("       ");
        printf("\n");
    }
}