This is part of code from my greedy.c

The purpose of this do while loop is to get a valid input.

I'm having trouble, I tested it outside do while loop and it was working fine.

I think that mistake is really dumb but I really need help!!

I'm stuck here... :-(

void calc(int number, int change, int coins)
{
int result = change / number;
coins = coins + result;
change = change % number;
}
int main(void)
{

int change;
do
{
    printf("How much I owe you: ");
    change = round(GetFloat() * 100);
} while (change < 0);
int coins = 0;
while (change > 0)
{
    if (change >= 25)
    {
        calc(25, change, coins);    
    }
    if (change >= 10)
    {
        calc(10, change, coins);  
    }
    if (change >= 5)
    {
        calc(5, change, coins);
    }
    if (change >= 1)  
    {
        calc(1, change, coins);
    }
}
printf("Minimum number of coins needed is: %i \n", coins);
return 0;

}