CPS 6, Quiz Questions, Jan 24--28, Spring 00

1. Write a main function that prompts the user to enter a positive integer. If the integer is negative an error message should be printed, otherwise print whether the number is odd or even (hint: if there is no remainder when divided by two, the number is even, use the modulus operator %). Sample output is shown below.

 prompt> checkint
 enter positive int: -3 
 -3 isn't positive, sorry
 prompt> enter positive int: 15 
 15 is odd
 prompt> enter positive int: 24 
 24 is even

2. The program below is Program 4.5, monthdays.cpp in the book.

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

// illustrates cascaded if/else statements

int main()
{
    string month;
    int days = 31;             // default value of 31 days/month
    cout << "enter a month (lowercase letters): ";
    cin >> month;
    
    if ("september" == month)
    {    days = 30;
    }
    else if ("april" == month)
    {    days = 30;
    }
    else if ("june" == month)
    {    days = 30;
    }
    else if ("november" == month)
    {    days = 30;
    }
    else if ("february" == month)
    {    days = 28;
    }
    cout << month << " has " << days << " days" << endl;
    return 0;
}

Modify the sequence of cascaded if/else statements so that there are two if statements, one for February and one that uses the OR operator ||. Hint, here are statements that checks if the month is january or february:

  string month;
  cout << "enter month: ";
  cin >> month;  
  if ( ("january" == month) || ("february" == month))
  {   cout << "you were born in the first two months" << endl;
  }
  else
  {   cout << "you cannot be an aquarius" << endl;
  }

3. (see pause/reflect 4.14) Write the function TriangleArea whose header is given below. It returns the area of a triangle given three sides of the triangle using the formula

  area = sqrt(s * (s - a) * (s - b) * (s - c) );

where a, b, and c are the sides of the triangle and s is is the semi-perimeter, or half the perimeter of the triangle.

  double TriangleArea(double a, double b, double c)
  // pre: a, b, c, are lengths of sides of a triangle
  // post: returns the area of the triangle whose sides are a,b,c
  {
      // write code here
  }

4. (see Exercise 4.7) Write a function (not main, just a function) that returns the surface area of a person. The surface area is given by the formula:

 surface area = 7.184-3 * weight0.452 * heigh0.725

where weight is in kilograms and height is in centimeters. Here's a main that calls the function, you must write the function:

  int main()
  {
     double height,weight;
     cout << "enter weight in kilos: ";
     cin >> weight;
     cout << "enter height in cm: ";
     cin >> height;

     double area = SurfaceArea(weight,height);
     cout << "Your surface area is: " << area << endl;
     return 0;
  }

5. (see exercise 4.2) Write a function that converts an integer in the range 1 to 10 to a roman numeral. The function should return a string so that IntToRoman(4) returns the string "IV" and IntToRoman(8) returns the string "VIII"

  string IntToRoman(int num)
  // precondition: 1 <= num <= 10
  // postcondition: returns Roman equivalent of num