remove action on invalid user entry

[brandys]

This program needs to state "Invalid entry" when the user input is outside the parameters set. It does this, but also posts the answer. How do I make it stop giving the F-C conversion when a user enters an invalid integer?

//Farenheit to Celcius
#include <iostream>
#include <string> //allows string inclusion
#include <iomanip> //allows manipulator
using std::cout;
using std::endl;
using std::showpos; //shows positive sign
using std::setw; //allows set w/ iomanip
using namespace std;
using std::fixed;
char ans; //assigns ans as character for loop do...while statement

int main()
{
cout <<

do //begins do statement
{
double Fahrenheit;
double Celsius;

cout << fixed;
cout << setprecision (2); //sets decimal point to 2
cout << showpos; //shows positive sign for positive integers


cout << "Enter Degrees Fahrenheit "; //gives directions to user for input
cin >> Fahrenheit; //sets value of fahrenheit
cout << endl; //creates a break in the lines

if (Fahrenheit <= 250 || Fahrenheit >= -250) //conditional values for user input
{
Celsius = (Fahrenheit - 32)* 5.0/9.0; //output formula
cout << "Celsius = " << Celsius << endl; //shows conversion answer
}

else (Fahrenheit >250 || Fahrenheit <-250); //conditional values for user input
{
cout << "Invalid entry.";
}

cout << "Would you like to enter another value? Enter 'y' to continue. "; //user prompt
cin >> ans; //sets answer for action
}
while (ans == 'y'); //assigns answer values for action
{
return 30; //returns to line 30 to reprompt for F value.
system("PAUSE"); //prevents screen closure
}


return 0;
}

[AbstractionAnon]

if (Fahrenheit <= 250 || Fahrenheit >= -250) 

Your if statement is faulty. You want an and condition, not an or condition.
A value of +300 is going to satisfy Fahrenheit >= -250 making the if condition true.
Likewise a value of -300, is going to satisfy Fahrenheit <= 250 also making the if condition true.

PLEASE USE CODE TAGS (the <> formatting button) when posting code.
http://v2.cplusplus.com/articles/jEywvCM9/
It makes it easier to read your code and it also makes it easier to respond to your post.
Hint: You can edit your previous post, highlight your code and press the <> formatting button.

[brandys]

Thanks for your help and timely answer. Sorry for not using tags. This is all very new to me!

PS: Thanks for not being a jerk about it.