Classic example of C language - find the minimum number of banknotes

Write a program , Ask the user to enter a dollar amount , Then show how to use the least 20 dollar 、10 dollar 、5 The dollar and 1 Dollars to pay :
 

# include <stdio.h>

int main()
{
	int amount;
	int twentyDollars = 0;// Definition 20 Number of US dollar bills 
	int tenDollars = 0;
	int fiveDollars = 0;
	int oneDollars = 0;

	printf("Enter an dollar amount: ");
	scanf("%d", &amount);

	twentyDollars = amount / 20;
	tenDollars = (amount - twentyDollars *20) / 10;// Calculation 10 Number of US dollar bills 
	fiveDollars = (amount - twentyDollars *20 - tenDollars *10) / 5;
	oneDollars = amount - twentyDollars *20 - tenDollars *10- fiveDollars;

	printf("$20 bills: %d\n", twentyDollars);
	printf("$10 bills: %d\n", tenDollars);
	printf("$5 bills: %d\n", fiveDollars);
	printf("$1 bills: %d\n", oneDollars);

	return 0;
}