CODEWITHSUNDEEP
c++
Quack
Quack

Reputation: 133

Why is this only returning whole numbers when i used double throughout?

Just wondering why this area calculation code only returns whole numbers, even though I used double throughout.

#include <iostream>

#define pi 3.14

piCalc(double radi) {
  double result;
  result = (radi * radi) * pi;
  return result;
}

int main() {
  double radius;
  std::cout << "Welcome to the circle area calculator. Please enter your radius"
            << std::endl;
  std::cin >> radius;
  std::cout << "your answer is " << piCalc(radius) << std::endl;
  std::cout << "thankyou for using the area calculator" << std::endl;
}

Even when i enter a float, for example 5.3, i still only return 88, when it should be 88.25. Thanks.

Upvotes: 0

Views: 151

Answers (1)

463035818_is_not_an_ai
463035818_is_not_an_ai

Reputation: 122133

Here:

piCalc(double radi){

You are missing the return type. This isn't valid C++. In (ancient?) C you could omit the return type and int was assumed. Some compilers still allow this as non-standard extension. Make the return type double:

double piCalc(double radi){

In general you need to take care with compiler extensions. For example gcc is rather lax with its default settings and compiles lots of code that shouldn't according to standard C++. -pedantic option can help to spot such undesired use of compiler specific extensions.

Upvotes: 5

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