Question

I am having issues with my program displaying information from different if statements when they shouldn’t be.
http://i53.tinypic.com/1zyx68.png

#include <iostream>
#include <string>
using namespace std;
int main( )
{
    string smreturn = "";
    string jointsingle = "";
    double income = 0.00;
double taxedincome = 0.00;
{
cout << "\nPlease enter your taxable income: ";
cin >> income;
while (income <= 0)
{
    cout << "\n Please enter a valid positive taxable income: ";
    cin >> income;
}
cout << "\n";
cout << "\nPlease press m if married and filing for a joint return, or s if filing for a single return: ";
cin >> smreturn;
            while (!(smreturn =="m") && !(smreturn =="M") && !(smreturn =="s") && !(smreturn =="S"))
{
    cout << "\nPlease press m if married and filing for a joint return,\n or s if filing for a single return: ";
    cin >> smreturn;
}

if (smreturn == "m" || "M")
{
    if (income >= 0 && income <= 1726)
    {
        taxedincome = income * .023;
    }
    if (income >= 1727 && income <= 3450)
    {
        taxedincome = (income - 1727) * .033 + 40;
    }
    if (income >= 3451 && income <= 5176)
    {
        taxedincome = (income - 3450) * .042 + 97;
    }
    if (income >= 5177 && income <= 6900)
    {
        taxedincome = (income - 5176) * .052 + 169;
    }
    if (income > 8626)
    {
        taxedincome = (income - 8626) * .07 + 362;
    }
        cout << "\nYour taxable income is:$" << (income);
cout << "\nAnd you are filing a joint return";
cout << "\nYour income tax will be:$" << (taxedincome);
cout << "\n";

}
if (smreturn == "s"||"S")
{
    if (income >= 0 && income <= 863)
    {
        taxedincome = (income * .023);
    }
    if (income >= 864 && income <= 1726)
    {
        taxedincome = (income - 863) * .033 + 20;
    }
    if (income >= 1727 && income <= 2588)
    {
        taxedincome = (income - 1726) * .042 + 48;
    }
    if (income >= 2589 && income <= 3450)
    {
        taxedincome - (income - 2588) * 0.052 + 85;
    }
    if (income >= 3451 && income <= 4313)
    {
        taxedincome - (income - 3450) * 0.06 + 129;
    }
    if (income > 4313)
        {
            taxedincome - (income - 4313) * 0.07 + 181;
}
        cout << "\nYour taxable income is:$" << (income);
cout << "\nAnd you are filing a single return";
cout << "\nYour income tax will be:$" << (taxedincome);
cout << "\n";
}
}           cout << "\n";
string returninfo;
if (smreturn == "s" || "S")
{
    returninfo == "single return";
}
else
{
    returninfo == "joint return";
}

system("PAUSE");
return 0;
}

It is displaying the info from both If statements, saving taxedincome as a single return for a joint return.

Answer 1

if (smreturn == "m" || "M")

should be

if ( (smreturn == "m") || (smreturn == "M") )

And mistakes like these in few other conditions. If you need to compare, you need to repeat it for each identifier in the if condition.