C Program for Number Comparison

1.write a program to perform following operation through enter user choice- 

1. for finding greatest no in given 2  number

2. for finding greatest no in given  3 number

3. for finding greatest no in given  4 number

   in this program we use( do while loop , switch case and if else condition 

   
   
   #include<stdio.h>
   
   #include<conio.h>
   void main()
   {
      int a,b,c,d,ch;
      clrscr();
      do
         {
            printf("\n1 for finding greatest no in  2 no");
            printf("\n2 for finding greatest no in 3 no");
            printf("\n3 for finding greatest no in 4 no");
            printf("\n0 for exit");
            scanf("%d",&ch);
            if(ch  >=  1  &&   ch  <=  3)
              {
                 printf("enter first no");
                 scanf("  %d  "   ,&a);
                printf("enter second no");
                scanf(" %d "    , &b);
                if(ch    >=   2)
                     {
                           printf("enter third no");
                           scanf("  %d  "  ,&c);
                           if(ch  ==  3)
                             {
                                  printf("enter fourth no");
                                  scanf("  %d  " ,&d);
                            }
                   }
            }
   switch(ch)
       {
         case 1:
                    if( a  ==   b )                                 
                        {
                            printf("these are equal value");
                        }
4.                   else if( a > b )
                       {
                         printf("%d  is greater than  %d ", a, b);
                        }
                   else
                       {
                        printf("%d  is greater than  %d", b, a);
                        }
                  break;
   case 2:
                  if(a > b  &&  a > c)
                          printf("%d  is greater than  %d  and %d" , a, b , c);
                  else if( b> c)
                         printf("%d  is greater than %d and %d", b, c, a);
                  else
                         printf("%d  is greater than %d and %d", c, a, b);
                 break;
   case 3:
                if(a > b  &&  a > c  &&  a > d)
                        printf("%d  is greater than %d , %d and %d", a, b, c, d);
               else if(b > c  &&  b > d)
                       printf("%d  is greater than %d, %d and %d", b, c, d, a);
               else if( c > d  )
                        printf("%d  is greater than %d, %d and %d", c, d, a, b);
               else
                        printf("%d is greater than %d, %d and %d", d, a, b, c);
               break;
   case 0:
              printf("oops! you press wrong key"); 
              break;
   default:
              printf("wrong choice");
     }
   }
   while(  ch  !=  0 );
   getch();
   }