#  include <stdio.h>
int main ()
  {
      char a,c;
      int b; 
      printf ("输入一个字符\n");
        scanf  ("%c",&a);
      if (a>=‘A‘&&a<=‘Z‘)
          {    
             c=a+32;
             printf ("%c\n",c);
           } 
      else if(a>=‘a‘&&a<=‘z‘)
               {
                    c=a-32;
                    printf ("%c\n",c);
           }    
      else if (a>=‘0‘&&a<=‘9‘)
            {
               b=a-48
               printf ("%d\n",b);
            }  
      else if (a==‘ ‘)
           {
              printf ("space\n",a);
           }
       else 
          {
             printf ("other\n",a);
          } 
       return 0;
  }
               

# include<stdio.h>
int main ()
{
        int a,b,c,x,y,z,e,f,g,h;
        printf ("输入你的生日年月日用英文逗号分开\n");
        scanf  ("%d,%d,%d",&a,&b,&c);
        if ((a<=0)||(b<=0||b>12)||(c<=0||c>31))
           {
                printf ("输入错误\n");
          }  
        if((a%4==0&&a%100!=0)||(a%400==0))
          {
            if((c>=30)&&(b==2))
              {
                printf("输入错误\n");
              } 
          }
        else if((a%4!=0)&&(b==2))
               {
                if(c>=29)
                  {
                      printf ("输入错误\n");
                   }
               
               }
        printf ("输入今天的日期年月日用逗号分开\n");
        scanf  ("%d,%d,%d",&x,&y,&z);
        if ((x<=0)||(y<=0||y>12)||(z<=0||z>31))
            {
                printf ("输入错误\n");
            } 
        if((x%4==0&&x%100!=0)||(x%400==0))
          {
            if((z>=30)&&(z==2)) 
               {
                 printf("输入错误\n");
               } 
          }
        else if((x%4!=0)&&(y==2))
               {
                 if(z>=29)
                   {
                      printf ("输入错误\n");
                   }
          }
        e=x-a;
        f=y-b;
        g=z-c;
        if (e==0)
           {
              if ((f>=0&&g>=0))
                 {
                    printf ("周岁为%d",e);
                 }
                else 
                    { 
                         printf ("输入错误\n");
                    }
           }
        else if (e>0)
                {  
                  if ((f==0&&g>0)||(f==0&&g==0))
                     {
                        printf ("周岁为%d",e);
                     }
                  else
                      { 
                          if(f==0&&g<0)
                            {   
                              h=e-1;
                               {
                                  printf("周岁为%d\n",h);
                               }
                            }
                      }
                   if (g==0&&f>0)
                      {
                            printf("周岁为%d\n",e);
                      }
                      else
                      {
                             if (g==0&&f<0)
                                {
                                  h=e-1;
                                  printf ("周岁为%d\n",h);
                                }
                      }
                    if ((f>0)&&(g>0||g<0))
                       {
                           printf ("周岁为%d\n",e);
                       }
                       else 
                            {
                                   if (f<0)
                                 {   
                                          h=e-1;
                                         printf ("周岁为%d\n",h);
                                 }
                            }
                }
    return 0; 
 } 

# include <stdio.h>
int main ()
{
    int a,b,c;
    printf ("输入三个整数判断\n");
    scanf ("%d,%d,%d",&a,&b,&c);
    if(a+b<=c||b+c<=a||a+c<=b)
      {
         printf ("非三角形\n"); 
      }
    else if ((a*a+b*b==c*c)||(b*b+c*c==a*a)||(a*a+c*c==b*b))
            {
                if(a==b||b==c||a==c)
                 { 
                   printf ("这个三角形为等腰直角三角形\n");
                 }
             
                 else 
                    {
                       printf ("这个为直角三角形\n");
                    }  
            }
    else if (a==b&&a==c&&b==c)
            {
               printf ("等边三角形\n");
            }
    else if ((a==b&&a!=c&&b!=c)||(b==c&&b!=a&&c!=a)||(a==c&&a!=b&&c!=b))
            { 
               printf ("等腰三角形\n");
             }
    else 
        {  
             printf("普通三角形\n");
        }
     return 0; 
}

# include <stdio.h>
# include <stdlib.h>
# include <time.h>
int main ()
{
    int a,b,c;
    srand(time(NULL));
    a=rand()%10+1;
    printf("这个商品为%d,猜它的价格\n");
    srand(a);
    b=rand()%100+1;
    printf("输入你的答案\n");
    scanf("%d",&c);
    if (b==c)
    {
        printf ("商品归你了,答案为%d\n",b);
        
    }
    else if(c>b)
    {
        printf("太大了,答案为%d\n",b);
    }    
        else 
        {
            printf ("太小了,答案为%d\n",b);
        }
        return 0;
}