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Converting Flowcharts into C++

  1. General tips
    1. All variables used in a flowchart must be "declared" at the top of main
    2. Our flowcharts have all been working with integers, so use the data type int in your programs 
      int x, y;
    3. C++ comparison/relational operators

      C++ Meaning
      < less than
      <= less than or equal to
      > greater than
      >= greater than or equal to
      == equals
      != not equals
    4. To calculate the remainder of X / Y, use the mod operator (%) 
      // r is the remainder of x / y
r = x % y;

cout << 5 % 2;  // 1
cout << 2 % 5;  // 2
  2. if-then-else
    if-then-else structure 
    if (a < 10)
{
	b = 2;
}
else
{
	b = 10;
}
  3. if-then
    if-then structure 
    if (a < 10)
{
	b = 2;
}
    1. The "yes" response must go to the process, and "no" must skip it
  4. Pre-test loop
    pre-test structure 
    c = 1;
while (c <= 5)
{
	cout << c;
	c = c + 1;
}
    1. The "yes" response must go into the loop, and "no" must leave it
  5. Post-test loop
    post-test structure 
    c = 1;
do
{
	cout << c;
	c = c + 1;
} while (c <= 5);
    1. The "yes" response must go into the loop, and "no" must leave it
    2. Don't forget the semicolon!
  6. Asking the "opposite" question
    Example if-then structure 
    if (x <= y)
{
	cout << x;
	x = x - 1;
}
    1. Since "yes" must go to the process and "no" skip it, you must ask the opposite question to convert into C++
    2. > ↔ <=
      < ↔ >=
      == ↔ !=
  7. Practice: Perfect Number flowchart
    Perfect number flowchart Show/hide solution 
    #include <iostream>
using namespace std;

void main()
{
	int n, t, d;
	
	cout << "Enter a number: ";
	cin >> n;
	
	t = 0;
	d = 1;
	
	while (d <= n/2)
	{
		if (n % d == 0)
		{
			t = t + d;
		}
		
		d = d + 1;
	}
	
	if (t == n)
	{
		cout << n << " is perfect.";
	}
	else
	{
		cout << n << " is NOT perfect.";
	}
}