#include <iostream>
using namespace std;

main()
{

    double weight = 0.00;
    double height = 0.00;
    double age = 0.00;
    int activityLevel = 0;
    double ALX = 0; //activityLevel multiplier

    cout << "Please enter your weight.\n";
    cin >> weight;
    cout << "Please enter your height.\n";
    cin >> height;
    cout << "Please enter your age.\n";
    cin >> age;

    cout << "Please specify your activity level.\n";
    cout << "1: Sedentary, little or no exercise, desk job.\n";
    cout << "2: Lightly active. (light exercise 1 to 3 times per week.\n";
    cout << "3: Moderately active. (Exercise 3 to 5 times per week.\n";
    cout << "4: Very active. (Exercise 6 to 7 times per week.)\n";
    cout << "5: Extra active.(Heavy exercise, multiple times per day.)\n";
    cin >> activityLevel;    //only 1-5 is valid input 
    

    if (activityLevel == 1)
        ALX = 1.2;
    else if (activityLevel == 2)
        ALX = 1.4;
    else if (activityLevel == 3)
        ALX = 1.6;
    else if (activityLevel == 4)
        ALX = 1.7;
    else if (activityLevel == 5)
        ALX = 1.9;
    if (activityLevel =! 1,2,3,4,5)         //??????????
        cout << "Please only enter numbers 1-5\n";

    cout << ALX << endl;                  // print debug

    return 0;
}

if (activityLevel != 1 && activityLevel != 2 && ...)

if (activityLevel < 1 || activityLevel > 5)

else

bool AcceptUserEntry(string & userEntry, size_t maxEntryChars);

bool IsUserEntryValid(string userEntry);

if (state is invalid)
  return error;

if (input is a)
  return answer for a;
else if (input is b)
  return answer for b;
else
  return generic answer;

#include <stdio.h>
#include <stdlib.h>
#include <math.h>
#include <time.h>

int extendedEuclid(int a, int b, int *x, int *y)	{
    int t, d;
    if (b == 0)	{
        *x = 1; *y = 0; return a;
    }
    d = extendedEuclid(b, a % b, x, y);
    t = *x; *x = *y; *y = t - (a/b)*(*y);
    return d;
}

//inverse of a, mod n
int modInverse(int a, int n)  {
    int x, y;
    extendedEuclid(a, n, &x, &y);
    return (x < 0) ? (x + n) : x;
}

int mont_mul(int N,int p,int x,int y)
{
	int w = modInverse(N,p);
	w= (p-w)&1; //%2

	int bit,u=0;
	int i;
	int k=0;
	for (i=1;i<=x;i=i*2)
	{
		bit = (x>>k)&1;
		u = u+(bit*y);		
		u = (u+ ((u*w)&1)*N);
		u = u>>1; //divide by 2
		k++;
	}

	if (u>=N)
	{
		u=u-N;
	}							

	return u;
}
int main()
{
	int x= 422;
	int y= 421;
	int N= 667; //must be co-prime with b
	int b= 2;
	int p = 1;
	while (p<N)
	{
		p = p*b;
	}

	int p_inverse = modInverse((p-N),N);
	int x_1=(x*p)%N;
	int y_1=(y*p)%N;
	//printf("x1=%d,y1=%d\n",x_1,y_1);
	int r = mont_mul(N,p,x_1,y_1);
	r = (r*p_inverse)%N;
	//r = mont_mul(N,p,r,1);
	int r2 = (x*y)%N;
	printf("%d, %d",r,r2);
	
}

/* This program takes input from the user and calculates
how many calories they burn per day */

#include <iostream>
using namespace std;

main()
{
    //initialize variables
    double weight = 0.00;                                   //double float variable for user's weight
    double height = 0.00;                                   //double float variable for user's height
    double age = 0.00;                                      //double float variable for user's age
    int activityLevel = 0;                                  //activityLevel variable restricted to integer input
    double ALX = 0.00;                                      //activityLevel multiplier
    double BMR = 0.00;                                      //Basic Metabolic Rate variable
    double DCB = 0.00;                                      //Daily Calories Burned variable

    //prompt user to input details
    cout << "Please enter your weight.\n";
    cin >> weight;
    cout << "Please enter your height.\n";
    cin >> height;
    cout << "Please enter your age.\n";
    cin >> age;

    //prompt user to specify activity level
    cout << "Please specify your activity level.\n";
    cout << "1: Sedentary, little or no exercise, desk job.\n";
    cout << "2: Lightly active. (light exercise 1 to 3 times per week.\n";
    cout << "3: Moderately active. (Exercise 3 to 5 times per week.\n";
    cout << "4: Very active. (Exercise 6 to 7 times per week)\n";
    cout << "5: Extra active. (Exercises two times per day. Includes running marathons, etc.)\n";
    cin >> activityLevel;


    //select multiplier based on user input
    //restrict input to integers 1-5
    if (activityLevel == 1)
        ALX = 1.2;
    else if (activityLevel == 2)
        ALX = 1.4;
    else if (activityLevel == 3)
        ALX = 1.6;
    else if (activityLevel == 4)
        ALX = 1.7;
    else if (activityLevel == 5)
        ALX = 1.9;
    else
        cout << "Please only enter numbers 1-5\n";


    BMR = 66 + (6.2 * weight) + (152.4 * height) - (6.8 * age);                             //BMR calculation
    DCB = ALX * BMR;                                                                        //DCB calculation

    cout << "You burn a total of "<< DCB << " calories each day. " << endl;                 //calculated output

    return 0;
}