Enumerated Type Example

	#include <iostream>
	#include <cctype>
	using namespace std;
	enum Work_Days {Monday, Tuesday, Wednesday, Thursday, Friday};
	Work_Days Convert(string day);
	int main()
	{
	string day_string;
	Work_Days day;
	cout << "Please enter a day of the work week (Monday
	through Friday): " “ << endl;
	cin >> day_string;
	day = Convert_work_days(day_string);
	cout << "The day is " << Convert_string(day) << endl;
	}

Enumerated Type Example

	Work_Days Convert_work_days(string day)
	{
	Work_Days result;
	switch(toupper(day[0]))
	{
	case 'M': result = Monday;
	break;
	case 'T': switch(toupper(day[1]))
	{
	case 'U': result = Tuesday; break;
	case 'H': result = Thursday; break;
	}
	break;
	case 'W': result = Wednesday;
	break;
	case 'F': result = Friday;
	break;
	}
	return result;
	}

Enumerated Type Example

	string Convert_string(Work_Days day)
	{
	string result;
	switch( day)
	{
	case Monday    : result = “Monday”;
	break;
	case Tuesday   : result = “Tuesday”;
	break;
	case Wednesday : result = “Wednesday”;
	break;
	case Thursday  : result = “Thursday”;
	break;
	case Friday    : result = “Friday”;
	break;
	}
	return result;
	}

Problem-Solving Case Study:
Finding the Area Under a Curve

	Problem: Find the area under the curve of the function x3 over an interval specified by the user.
	Input: Two floating-point numbers specifying the interval over which to find the area, and an integer number of intervals to use in approximating the area.

Problem-Solving Case Study:
Finding the Area Under a Curve

	Output: The input data (echo print) and the value calculated for the area over the given interval.
	Discussion: Our approach is to compute an approximation by dividing the area into equal width rectangular strips. Smaller widths give a better answer. We can use a value-returning function to compute the area of each rectangle.

Problem-Solving Case Study:
Finding the Area Under a Curve

Problem-Solving Case Study:
Finding the Area Under a Curve

Problem-Solving Case Study:
Finding the Area Under a Curve

Problem-Solving Case Study:
Finding the Area Under a Curve

	Main
		Get data
		Set width = (high – low)/divisions
		Set area = 0.0
		Set leftEdge = low
		For count going from 1 through divisions
			Set area = area + RectArea(leftEdge, width)
			Set leftEdge = leftEdge + width
		Print area

Problem-Solving Case Study:
Finding the Area Under a Curve

	RectArea (In: leftEdge, width) Out: Function value
		Return Funct(leftEdge + width/2.0) * width
	Get Data (Out: low, high, divisions)
		Prompt for low and high
		Read low, high
		Prompt for divisions
		Read divisions
		Echo print input data
	Funct (In: x) Out: Function value
	Return x*x*x

Problem-Solving Case Study:
Finding the Area Under a Curve

	float Funct( float );
	void  GetData( float&, float&, int& );
	float RectArea( float, float );
	int main()
	{
	float low; float high; float width; float leftEdge;
	float area; int divisions; int   count;
	GetData(low, high, divisions);
	width = (high - low) / float(divisions);
	area = 0.0; leftEdge = low;
	for (count = 1; count <= divisions; count++)
	{
	area = area + RectArea(leftEdge, width);
	leftEdge = leftEdge + width;
	}
	cout << "The result is equal to "
	<< setprecision(7) << area << endl;
	}

Problem-Solving Case Study:
Finding the Area Under a Curve

	void GetData( /* out */ float& low,         // Bottom of interval
	/* out */ float& high,        // Top of interval
	/* out */ int&   divisions )  // Division factor
	// Postcondition:
	//     All parameters (low, high, and divisions)
	//     have been prompted for, input, and echo printed
	{
	cout << "Enter low and high values of desired interval"
	<< " (floating point)." << endl;
	cin >> low >> high;
	cout << "Enter the number of divisions to be used (integer)."   << endl;
	cin >> divisions;
	cout << "The area is computed over the interval “ << low
	<< endl << "to " << high << "   with " << divisions
	<< " subdivisions of the interval." << endl;
	}

Problem-Solving Case Study:
Finding the Area Under a Curve

	float RectArea( /* in */ float leftEdge,    // Left edge of
	//   rectangle
	/* in */ float width )   // Width of rectangle
	// Computes the area of a rectangle that starts at leftEdge and is
	// "width" units wide. The height is given by the value
	// computed by Funct at the horizontal midpoint of the rectangle
	// Precondition:
	//     leftEdge and width are assigned
	// Postcondition:
	//     Function value == area of specified rectangle
	{
	return Funct(leftEdge + width / 2.0) * width;
	}

Problem-Solving Case Study:
Finding the Area Under a Curve

	float Funct( /* in */ float x )    // Value to be cubed
	// Computes x cubed.  You may replace this function with any
	// single-variable function
	// Precondition:
	//     The absolute value of x cubed does not exceed the
	//     machine's maximum float value
	// Postcondition:
	//     Function value == x cubed
	{
	return x * x * x;
	}