实验二.

test1

#include <stdio.h>
#include <stdlib.h>
#include <time.h>
#define N 5
#define N1 374
#define N2 465
int main()
{
    int number;
    int i;
    srand(time(0));
    for (i = 0; i < N; ++i) {
        number = rand() % (N2 - N1 + 1) + N1;
        printf("202383290376%04d\n", number);
    }
    return 0;
}

1.随机生成一个数赋值给number
2.以当前系统时间作为随机种子,随机生成一个数

#include<stdio.h>
int main()
{
    char light;
    while ((light=getchar()) != EOF)
    {
        switch (light)
        {
        case 'r':printf("stop\n");break;
        case 'g':printf("go go go\n");break;

        case 'y':printf("wait a muinte\n");break;
        default :printf("something wrong");break;
        }
　　

getchar();
    }
    return 0;

}


test 3

#include<stdio.h>
#include<stdlib.h>
#include<time.h>
int main()
{
    int a, b = 1, c, d = 0;
    srand(time(0));
    a = rand() % 30+1;
    for (b = 1;b <= 3;b++)
    {
        scanf_s("%d", &c);
        if (c < a) {
            printf("早了\n");
            d += 1;
        }
        else if (c > a) {
            printf("晚了\n");
            d += 1;
        }
        else if (c == a) {
            printf("中了\n");break;
        }
    }
    if (d = 3) {
        printf("次数用完了\n");
    }

 return 0;
}

test 4

#include<stdio.h>
int main()
{
    int a, n;
    double every,s;
    int down,time;
    while (scanf_s("%d%d", &n,&a) != EOF) {
        for (time = 1,down=0,s=0;time <= n;time++) {
            down = down*(time-1)*10 + a;
            every = (time*1.0) / (down*1.0);
            s = every + s;
        }
        printf("%f\n", s);
    }
    return 0;
}

21:22:09

test 5

#include<stdio.h>
#include<math.h>
int main()
{
    int i, j;
    int a=1;

    for (i = 1, j = 1,a=1;j < 10;j++,a++) {
        for (i = 1;i <=a;i += 1) {
                printf("%d*%d=%d    ", i, j, i * j);
            }
            printf("\n");
        }


    return 0;
}

#include<stdio.h>
int main()
{    
    int n;
    int i, j,m;
    scanf_s("%d", &n);
    for (j = 1;j <= n;j++) {
        for (m = 1;m <= j;m++) {
            printf("\t");
        }
        for (i = 1;i <= (2 * n -(j*2-1));i++) {
            printf(" o\t");
        }
        printf("\n");
        for (m = 1;m <= j;m++) {
            printf("\t");
        }
        for (i = 1;i <= (2 * n - (j * 2 - 1));i++) {
            printf("<H>\t");
        }
        printf("\n");
        for (m = 1;m <= j;m++) {
            printf("\t");
        }
        for (i = 1;i <= (2 * n - (j * 2 - 1));i++) {
            printf("I I\t");

        }
        printf("\n");


    }


    return 0;
}