A Program for Selection Sort Algorithm...!!

/*Selection sorting selects the initially the first element as minimum valued and compare it with the all elements*/
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#include<stdio.h>
#include<conio.h>
#include<stdlib.h>
#define FNAME1 "best case"
#define FNAME2 "avg case"
#define FNAME3 "wrost case"

FILE *f1,*f2,*f3;
void main()
{
 int i,j,ch,n,k,min,minpos,a[10000];
 int count=0;
 clrscr();
 printf("1-> Best case\t2-> Average case\t 3-> Worst case\n\n");
 printf("Enter your choice:");
 scanf("%d",&ch);
 printf("Enter the size of elements of file\t:");
 scanf("%d",&n);


       switch(ch)
 {
  case 1:
   f1=fopen(FNAME1,"w");
   for(i=0;i<n;i++)
   {
    a[i]=i;
    printf("%d\t",a[i]);
    fprintf(f1,"%d\n",a[i]);
   }
   fclose(f1);
 
   f1=fopen(FNAME1,"r");
   i=0;
   while(!feof(f1))
   {
    fscanf(f1,"%d\n",&a[i]);
    i++;
   }
   fclose(f1);
         
                        for(i=0;i<n;i++)  //sorting loop
          {
       min=a[i];
       minpos=i;
   for(j=i+1;j<n;j++)
   {
       if(min>a[j])
       {
          count++;
          min=a[j];
          minpos=j;
        }
   }
   a[minpos]=a[i];
   a[i]=min;
   }                //sorting loop ends
   printf("After Sorting... \n");
   for(i=0;i<n;i++)
   {
      fscanf(f1,"%d\n",&a[i]);
      printf("%d\t",a[i]);
   }
   printf("The total counts required:%d",count);
  break;
  case 2:
   f2=fopen(FNAME2,"w");
   for(i=0;i<n;i++)
   {
       k=rand();
       fprintf(f2,"%d\t",k);
   }
   fclose(f2);
   f2=fopen(FNAME2,"r");
   i=0;
   while(!feof(f2))
   {
         fscanf(f2,"%d\t",&a[i]);
         printf("%d\t",a[i]);
         i++;
   }
   fclose(f2);
   for(i=0;i<n;i++)  //sorting loop
   {
       min=a[i];
       minpos=i;
   for(j=i+1;j<n;j++)
   {
       if(min>a[j])
       {
          count++;
          min=a[j];
          minpos=j;
        }
   }
   a[minpos]=a[i];
   a[i]=min;
   }                //sorting loop ends
   printf("After Sorting... \n");
   for(i=0;i<n;i++)
   {
      fscanf(f1,"%d\n",&a[i]);
      printf("%d\t",a[i]);
   }
   printf("The total counts required:%d",count);
  break;

  case 3:
   f3=fopen(FNAME3,"w");
   i=n-1;
   j=0 ;
   while(i>=0)
   {
    a[j]=i;
    fprintf(f3,"%d\n",a[i]);
    printf("%d\t",a[j]);
    i--;
    j++;
   }
   fclose(f3);
   for(i=0;i<n;i++)  //sorting loop
   {
       min=a[i];
       minpos=i;
   for(j=i+1;j<n;j++)
   {
       if(min>a[j])
       {
          count++;
          min=a[j];
          minpos=j;
        }
   }
   a[minpos]=a[i];
   a[i]=min;
   }                //sorting loop ends
   printf("After Sorting... \n");
   for(i=0;i<n;i++)
   {
      fscanf(f1,"%d\n",&a[i]);
      printf("%d\t",a[i]);
   }
   printf("The total counts required:%d",count);
  break;
      }
 getch();
}
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