Bills and coin denomination program
You have a lot of copy-and-paste code, where the only things that vary are the variable name, denomination, and textual description.  You can generalize the logic.

#include &lt;iostream&gt;

struct Denomination {
    const int cents;
    const char *description;
};

const Denomination DENOMINATIONS[] = {
    { 10000, "Hundred-Dollar Bills" },
    {  5000, "Fifty-Dollar Bills" },
    {  2000, "Twenty-Dollar Bills" },
    {  1000, "Ten-Dollar Bills" },
    {   500, "Five-Dollar Bills" },
    {   100, "One-Dollar Bills" },
    {    25, "Quarters" },
    {    10, "Dimes" },
    {     5, "Nickels" },
    {     1, "Pennies" }
};

int main() {
    double totalAmount;
    std::cout &lt;&lt; "Please enter the amount to convert: $";
    std::cin &gt;&gt; totalAmount;
    std::cout &lt;&lt; '\n';

    int cents = 100 * totalAmount;
    for (int i = 0; i &lt; sizeof(DENOMINATIONS) / sizeof(DENOMINATIONS[0]); ++i) {
        std::cout &lt;&lt; "Number of " &lt;&lt; DENOMINATIONS[i].description
                  &lt;&lt; ": " &lt;&lt; (cents / DENOMINATIONS[i].cents) &lt;&lt; '\n';
        cents %= DENOMINATIONS[i].cents;
    }
}


Also note:


A somewhat common convention is to use this NamingConvention for types, this namingConvention for variable names, and this NAMING_CONVENTION for constants.
Your DollarsConversion variable is misnamed, in my opinion, as it actually stores the number of cents.