after I put in all my numbers and the result is displayed I get a huge or tiny number. Not sure what the problem is.
#include <iostream>
using namespace std;
int main()
{
//Declare Variables
int height, age;
double weight, bmr;
char gender;
//Input
cout<< "Enter your weight in pounds\n";
cin>> weight;
cout<< "Enter your height in inches\n";
cin>> height;
cout<< "Enter your age in years\n";
cin>> age;
cout<< "Enter male or female\n";
cin>> gender;
char gender can store only one character but you are checking that if it is equal to "male" i.e they are four characters.
66 + (6.3 * weight) + (12.9 * height) - (6.8 * age);
you are niether assigning it to any variable nor using it in any other way.better assign to some variable to use it.