Beginner C++ help

[finalcloud13]

#include <iostream>
#include <string>
using namespace std;

int main ()
{
int i, f, m;
string n;
double a = 2.60;
double b = 3.36;
double c = 2.79;
double t;

cout << "Initial meter reading:";
cin >> i;
cin.ignore(100000, '\n');

cout << "Final meter reading:";
cin >> f;
cin.ignore(100000, '\n');

int hcf = f - i;

cout << "Customer name:";
cin >> n;
cin.ignore(100000, '\n');

cout << "Month number (1=Jan, 2=Feb, etc.):";
cin >> m;
cin.ignore(100000, '\n');

if (m == 6 || 7 || 8 || 9 || 10)
{
if (hcf <= 46)
{
t = hcf * a;
}
else if (hcf > 46)
{
t = ((hcf - 46)*b) + 119.60;
}
}
else
{
if (hcf <= 32)
{
t = hcf * a;
}
else if (hcf > 32)
{
t = ((hcf - 32)*c) + 83.20;
}
}
cout << "---\nThe bill for " << n << " is $" << t << "\n";
}

The problem is in regards to the bolded part. I have the condition only if m is a number 6-10, but any number I input, it still uses the bold code block instead of going to the italicized else block. What am I doing wrong? And, how do I make it that in the underlined output, the number is always shown as a nonnegative number with at least one digit to the left and exactly two digits to the right of the decimal point?

Also, I'm not understanding too well why I don't get an error for using double, but I do for float. I thought float could be used for decimals too.

Please point out any mistakes in the code or anything that is not needed yet included in there. Thanks in advance.

[kram 2.0]

Try rephrasing the top bolded conditional as such:
if (m >=6 && m <=10)
{
...

Where, of course, the "..." will be the rest of your code.

kram

[blue60007]

Is it even valid to do m == 6 || 7 ... would think you would have to do m == 6 || m == 7. Seems counter-intuitive, but I'm not sure that's a valid boolean expression.

Can you provide a couple examples of what is being outputted for t, and what you are expecting? You are getting something like x.xx ? Might make more sense to me to see what you're expecting.

[finalcloud13]

Thank you very much, the

if (m >=6 && m <=10)
{

fixed the problem :)