我正在制作一个简单的算法，该算法仅使用25c，10c，5c和1c硬币，返回键入$值时需要找回的最小硬币数目。

例如欠款额：0.31 硬币：3

请参见下面的代码，它会正确提示用户，但在输入时不会返回任何数字。

#include <cs50.h>
#include <stdio.h>
#include <math.h>

int main(void)

{
    //Declaring the variables
   float change_owed;
   int quarter,dime,nickel,penny;
    //Defining types of coins that can be given as change.
    quarter = 25;
    dime = 10;
    nickel = 5;
    penny = 1;

    do
    {
    //Defining function and storing in variable change
        change_owed = get_float("Change: ");
    }  
    //Repeat prompt while input is negative  
    while (change_owed <= 0);
    //rounding the numbers so we can divide
    int amount = round(change_owed * 100);

    ///Deciding if to use a Quarter
    //Defining Quarter counter
    int count_quarter=0;
    while (amount >= quarter)
    {   
        //Counting number of quarters used
        count_quarter++;
        //Decreasing amount owed by a quarter
        return amount - quarter;
    }
    //Deciding whether to use a dime
    //Defining dime counter
    int count_dime=0;
    while (amount >= dime)
    {
        //Counting number of dimes used
        count_dime++;
        //Decreasing amount owed by a dime
        return amount - dime;
    }
    int count_nickel=0;
    while (amount >= nickel)
    {
       //Deciding whether to use a nickel
       //counting number of nickels used 
        count_nickel++;
        //Decreasing amount by a nickel
        return amount - nickel;
    }

    //Deciding whether to use a penny
    //Defining penny counter
    int count_penny=0;
    while (amount >= penny)
    {
       //counting number of pennies used
        count_penny++;
      //Decreasing amount by a penny
      return amount - penny; 
    }

  int total_coins = (count_quarter + count_dime + count_nickel + count_penny);

    printf("%i",total_coins);

}