Thread: newbie ?

What would be the best way to stop this from looping ? when an Invalid character such as a letter is input for the sale amount ?

Code:

#include <stdio.h>
   float fAmount;
    main()
     {   
      int iSelection = 0; 
      float fAmount = 0.0;//Purchased amount in US$
      float fTax1 = .0725;//Del Mar CA.
      float fTax2 = .0750;//Encinitas CA.
      float fTax3 = .0775;//La Jolla CA.
 
      printf("\n\tSelect the store location\n");
      printf("1\tDel Mar\n");
      printf("2\tEncinitas\n");
      printf("3\tLa Jolla\n");
      scanf("%d", &iSelection);
  
    // This makes the program run in a loop if an incorrect value is input for Purchased amount.
     do
     {
      printf("\nEnter Amount in US $\n");
      scanf("%f", &fAmount);
     }while((fAmount - floor(fAmount)) == 0.0); 
    
  
   //This calculates the tax rate for Del Mar CA. 
      if (iSelection == 1) {
      printf("\nYour tax amount is: $%.2f and the total price is $%.2f\n", (fAmount * fTax1), (fAmount + (fAmount * fTax1)));
      printf("\nClick the X in the upper right corner to exit this application.\n");
     } //end if
          
   //This calculates the tax rate for Encinitas CA. 
      if (iSelection == 2) {
      printf("\nYour tax amount is: $%.2f and the total price is $%.2f\n", (fAmount * fTax1), (fAmount + (fAmount * fTax1))); 
      printf("\nClick the X in the upper right corner to exit this application.\n");
     } //end if
 
   //This calculates the tax rate for La Jolla CA. 
      if (iSelection == 3) {
      printf("\nYour tax amount is: $%.2f and the total price is $%.2f\n", (fAmount * fTax1), (fAmount + (fAmount * fTax1)));
      printf("\nClick the X in the upper right corner to exit this application.\n");
     } //end if
   
 
  getch();
      return 0;
    
     }