What would probably help him are suggestions how to achieve better readability...
Watch those linebreaks. Set them at logical borders. Only one at a time. Example of better formatting:
Code:
int main( int argc, char* argv[] )
{
int length = 0;
int width = 0;
int area = 0;
double discount = 0;
cout << "Length of room (feet)? ";
cin >> length;
cout << "Width of room (feet)? ";
cin >> width;
cout << "Customer discount (precent)? ";
cin >> precentDis;
cout << "Cost per square foot (xxx.xx)? ";
cin >> priceCarpet;
Each logical Unit ( Ask for input X, get input X ) now resides in one optical block.
Also, use more spaces. Don't put all your code into one line without breaks. Breaks at logical borders make reading easier.
Indentation:
each { forces an additional level of indentation, each } takes one back. In your main, the variable declarations are on the same line as the {. Put a tab there for each line. Other functions miss tabs at all.
As you know how to use arguments and return data in functions, get rid of the global variables.