Answer to Question #183281 in C++ for Mridul

Question

Radioactive decay of radioactive materials can be modeled by the equation A = A0e −t(log2/h) where A is amount of material at time t, A0 is the material at time 0, and h is the half-life of the radio active material. Technetium-99m is a radioisotope that is used in imaging of the brain. It has a half-life of 6 hours. Your program should display the relative amount of A/A0 in a patient body every hour for 24 hours after receiving the a dose. Prompt user for the initial dose (A0) in millicuries (mci). Typical values range from 3.8 - 15 millicuries. However, you can use any value for this program. Even milligrams. Enter values without negative exponents. If you want to enter 15 milligrams, enter 15. Same, for millicuries. 1Display your results in a table, the first column showing hours beginning at 0, and ending at 24. The second column shows the ratio of A/A0 beginning at hour 0 when the ratio is 1. Make sure that only positive values are entered for the initial dose using a do/while loop.

Answer 1

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


int main()
{
    const int h = 6;
    double A0;
    // checking the correctness of entering a positive number
    for (;;)
    {
        cout << "Enter a positive starting dose (A0): ";
        if ((cin >> A0).good() && (A0 > 0)) break;
        cout << "Invalid value entered, please re-enter" << endl;
        if (cin.fail())
        {
            cin.clear();
            cin.ignore(cin.rdbuf()->in_avail());
        }
     }
   //  ratio of A/A0 = e^(-t*log2/h)
    cout << "hours" << "     ratio  A/A0" << endl;
    // h = 0 
    cout << setw(5) <<0<< setw(16)<< 1 << endl;
    for (int t = 1; t < 25; t++) 
    {
        cout << setw(5) << t << setw(16) << exp(-t*log(2)/h) << endl;
    }
    return 0;
}