Program to write to a file and display the vowel which occurred the most

Program to write to a file and display the vowel which occurred the most often. If you need help comment below

#include<stdio.h>

main()

{

  FILE *f1;

  char c;

  int a,e,i,o,u;

  a=0;

  e=0;

  i=0;

  u=0;

  o=0;

  printf("\nEnter the letters to the file:\n");

  f1=fopen("TEXT.txt","w");

  while((c=getchar())!='\n')

    putc(c,f1);

  fclose(f1);

  f1=fopen("TEXT.txt","r");

  while((c=getc(f1))!=EOF)

   {

     if(c=='a')

       a++;

     else if(c=='e')

       e++;

     else if(c=='i')

       i++;

     else if(c=='o')

       o++;

     else if(c=='u')

       u++;

   }

  fclose(f1);

  if((a>=e)&&(a>=i)&&(a>=o)&&(a>=u))

   printf("\n\n'a'is the vowel which occured the most.\n%d times",a);

  if((e>=a)&&(e>=i)&&(e>=u)&&(e>=o))

   printf("\n\n'e' is the vowel which occured the most.\n%d times",e);

  if((i>=a)&&(i>=e)&&(i>=o)&&(i>=u))

   printf("\n\n'i' is the vowel which occured the most.\n%d times",i);

  if((o>=a)&&(o>=e)&&(o>=i)&&(o>=u))

   printf("\n\n'o'is the vowel which occured the most.\n%d times",o);

  if((u>=a)&&(u>=e)&&(u>=i)&&(u>=o))

   printf("\n\n'u' is the vowel which occured the most.\n%d times",u);

  printf("\n\n");

}