#include<stdio.h>//1.三角形
int main()
{
    
    printf("*\n");
    printf("**\n");
    printf("***\n");
    printf("****\n");
    printf("*****\n");
    printf("******\n");
    printf("*******\n");
    printf("********\n");
    printf("*********\n");
    printf("**********\n");
    
}

#include<stdio.h>//2.十行矩形 
int main()
{
    printf("**********\n");
    printf("**********\n");
    printf("**********\n");
    printf("**********\n");
    printf("**********\n");
    printf("**********\n");
    printf("**********\n");
    printf("**********\n");
    printf("**********\n");
    printf("**********\n");
}

#include<stdio.h>//3.倒三角形 
int main()
{
    printf("**********\n");
    printf("*********\n");
    printf("********\n");
    printf("*******\n");
    printf("******\n");
    printf("*****\n");
    printf("****\n");
    printf("***\n");
    printf("**\n");
    printf("*\n");
}

#include<stdio.h> // 4.五级制成绩 
int main()
{
    char score;
    scanf("%c",&score);
    switch (score)
    {
        case ‘A‘:
              printf("90~100");
              break;
        case ‘B‘:
              printf("80~89");
              break; 
        case ‘C‘:
              printf("70~79");
              break;
        case ‘D‘:
              printf("60~69");
              break;
        case ‘E‘:
              printf("0~59");
              break; 
    }   
}

#include<stdio.h> //6.100米小球落下 
#define G 9.8 
int main()
{
    int y=3;
    printf("垂直距离是：%.2f\n",0.5*G*y*y);
    
    
}

#include<stdio.h> //7. 显示个位数字，十位数字和百位数字的值。 
#include<math.h> 
int main()
{
    int t[10]={0};
    int a;
    scanf("%d",&a);
    int i=0;
    while(a!=0)
    {
        t[i++]=a%10;
        a=a/10;
    }
    int j;
    for(j=0;j<=i;j++)
         printf("%.0f",(t[j]*pow(10,j)));
}

#include<stdio.h>//8.分段函数
#include<math.h>
int main ()
{
    double x;
    double y;
    scanf("%lf",&x);
    if(x>=0)
         y=sqrt(x);
     else
         y=pow(x+1,2)+2*x+1/x;
         printf("f(x)=%f",y);
         
}