Confused between the usage of constructors and what to/what not to place in them. : <p>I had basics in C, and I've just started programming in c++ two weeks ago, and find 'classes' confusing. My question is how do i put a 'cin' to input the value to determine marks, and also how do i print the grades based on the below code? I'm only printing A to F and i'm so blur right now. And for some reason if i put 'else if' instead of just 'if' the error reads as missing ; before cout. Have way too many questions, sorry about that.. </p>

<pre><code>#include &lt;iostream&gt;   
using namespace std;

class StudentMark {
private:
float mark;

public:
StudentMark() //constructor
{
mark = 0.0;
cout &lt;&lt; "Constructed an instance of class StudentMark\n";
}

void SetMark(float markofstudent)
{
mark = markofstudent;
}

void IntroduceMark()
{

if (80&lt;mark&lt;100)
cout &lt;&lt; "A" &lt;&lt; endl;

if (65&lt;mark&lt;79)
cout &lt;&lt; "B" &lt;&lt; endl;

if (50&lt;mark&lt;64)
cout &lt;&lt; "C" &lt;&lt; endl;

if (40&lt;mark&lt;49)
cout &lt;&lt; "D" &lt;&lt; endl;

if (0&lt;mark&lt;39)
cout &lt;&lt; "F" &lt;&lt; endl;
}
};

int main()
{
StudentMark FirstStudent;

FirstStudent.SetMark(89);

FirstStudent.IntroduceMark();
}
</code></pre>
