Real-Life Math and Booleans

Real-Life Math and Booleans

Let's put math functions and booleans to work in a small practical program.

Price comparison

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

int main() {
  double shopA = 12.50;
  double shopB = 11.99;
  bool cheapShop = shopA < shopB;
  cout << "Shop A is cheaper: " << cheapShop << endl;
  return 0;
}

The comparison shopA < shopB is evaluated into a boolean. Cheap shop is a decision the program can make.

Voting age check

int age = 20;
int votingAge = 18;
bool canVote = age >= votingAge;
cout << canVote << endl;  // true

A single bool stores the answer for any voter.

Distance with math

cout << sqrt(9) + 1 << endl;        // 4
double distance = pow(3, 2) - 5;    // 4
cout << (distance > 3) << endl;     // true

Keep it readable

• Store the result of a comparison in a bool variable.
• Use math to compute, booleans to decide.
• Clear names make programs easier to understand.

TL;DR

• Use math functions from <cmath> in real programs.
• Turn comparisons into decisions with booleans.
• Store comparisons in bool variables.
• Print a bool to see 1 (true) or 0 (false).