alright i have been LEARNING C++ from a book and i have gotten pretty alright with it but the person whowrote it must be well not very bright he didnt TELL you what to make the exetension i was trying to run this program but i didnt know the exetention i tryed .c but it didnt work so does anyone know what it is oo yea can u guys look at my script its doin math

#include
#include
#include
/*
Name: billy
Author: billy
Description: A General Formula Program made in C++
Date: 10/17/05
Copyright: i dont know
*/



//Universal variable for pi
float pi = 3.14;

//Forumla used for Distance formula
int f_Distance()
{
//Declare the variables
float x_Sub1, x_Sub2, y_Sub1, y_Sub2, y_Answer, x_Answer, f_Answer;

//User inputs here
cout << "\n\nPlease INSERT Ysub2: ";
cin >> y_Sub2;
cout << "Please insert Ysub1: ";
cin >> y_Sub1;
cout << "Please insert Xsub2: ";
cin >> x_Sub2;
cout << "Please insert Xsub1: ";
cin >> x_Sub1;

//The actual calculations
y_Answer = (y_Sub2 - y_Sub1) * (y_Sub2 - y_Sub1);
x_Answer = (x_Sub2 - x_Sub1) * (x_Sub2 - x_Sub1);
f_Answer = sqrt (y_Answer + x_Answer);

//The Final Answer
cout << "\n\nThe distance is " << f_Answer;
}

//Formula used for Midpoint
int f_Midpoint ()
{
//Declaring the variables
float x_Sub1, x_Sub2, y_Sub1, y_Sub2, y_Answer, x_Answer;

//User inputs here
cout << "\n\nPlease insert Xsub1: ";
cin >> x_Sub1;
cout << "Please insert Xsub2: ";
cin >> x_Sub2;
cout << "Please insert Ysub1: ";
cin >> y_Sub1;
cout << "Please insert Ysub2: ";
cin >> y_Sub2;

// Formula Calculations
x_Answer = ((x_Sub1 + x_Sub2)/2);
y_Answer = ((y_Sub1 + y_Sub2)/2);

//Final answer output
cout << "\n\nThe Mid-Point is (" << x_Answer << "," << y_Answer << ")";
}

//Formula for the circumference of a circle
int f_Circumference ()
{
//Declaring variables
float f_Diam, f_Answer;

//User inputs here
cout << "\n\nPlease insert the Diameter: ";
cin >> f_Diam;

//Calculations
f_Answer = (f_Diam * pi);

//Final answer Output
cout << "\n\nThe Circumference is " << f_Answer;
}

//Formula for area of a circle
int f_Areacircle ()
{
//Declaring variables
float f_Radius;
float f_Answer;

//User inputs here
cout << "\n\nPlease insert the Radius: ";
cin >> f_Radius;

//Calculations
f_Answer = ((f_Radius * f_Radius) * pi);

//Final Answer output
cout << "\n\nThe Area of the Circle is " << f_Answer;
}


int main()
{
//Declaring the variable for the SWITCH statement
int choice;

//The layouyt of the program
cout << "-----Basic Geometry Formulas-----\n\n\n";
cout << "1. Distance Formula\n";
cout << "2. Mid-point Formula\n";
cout << "3. Circumference\n";
cout << "4. Area of a Circle\n\n";
cout << "Please select a choice: ";
choice = getchar();

//Switch statement between the various formulas that the user picks
switch(choice){
case '1':
f_Distance();
break;
case '2':
f_Midpoint();
break;
case '3':
f_Circumference();
break;
case '4':
f_Areacircle();
break;
default :
return -1;
}
//Pause for one Key and close...
cin.ignore();
cin.get();
return 0;
}


k thanksIt really depends on the complier you're using. In general C programs have a extension of .C and C++ programs have .cpp


Hope this helps.