C++ Programming Code Examples
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Virtual functions with person class
/* Virtual functions with person class */
#include <iostream>
using namespace std;
class person{
protected:
char name[40];
public:
void getName()
{ cout << " Enter name: "; cin >> name; }
void putName()
{ cout << "Name is: " << name << endl; }
virtual void getData() = 0;
virtual bool isOutstanding() = 0;
};
class student : public person{
private:
float gpa;
public:
void getData(){
person::getName();
cout << " Enter student's GPA: "; cin >> gpa;
}
bool isOutstanding()
{
return (gpa > 3.5) ? true : false;
}
};
class professor : public person{
private:
int numPubs;
public:
void getData(){
person::getName();
cout << " Enter number of professor's publications: ";
cin >> numPubs;
}
bool isOutstanding()
{
return (numPubs > 100) ? true : false;
}
};
int main(){
person* persPtr[100];
int n = 0;
char choice;
do {
cout << "Enter student or professor (s/p): ";
cin >> choice;
if(choice=='s')
persPtr[n] = new student;
else
persPtr[n] = new professor;
persPtr[n++]->getData();
cout << " Enter another (y/n)? ";
cin >> choice;
} while( choice=='y' );
for(int j=0; j<n; j++){
persPtr[j]->putName();
if( persPtr[j]->isOutstanding() )
cout << " This person is outstanding\n";
}
return 0;
}
The main purpose of C++ programming is to add object orientation to the C programming language and classes are the central feature of C++ that supports object-oriented programming and are often called user-defined types. A class is used to specify the form of an object and it combines data representation and methods for manipulating that data into one neat package. The data and functions within a class are called members of the class.
In computer programming, we use the if statement to run a block code only when a certain condition is met. An if statement can be followed by an optional else statement, which executes when the boolean expression is false. There are three forms of if...else statements in C++: • if statement, • if...else statement, • if...else if...else statement, The if statement evaluates the condition inside the parentheses ( ). If the condition evaluates to true, the code inside the body of if is executed. If the condition evaluates to false, the code inside the body of if is skipped.
In while loop, condition is evaluated first and if it returns true then the statements inside while loop execute, this happens repeatedly until the condition returns false. When condition returns false, the control comes out of loop and jumps to the next statement in the program after while loop. The important point to note when using while loop is that we need to use increment or decrement statement inside while loop so that the loop variable gets changed on each iteration, and at some point condition returns false. This way we can end the execution of while loop otherwise the loop would execute indefinitely. A while loop that never stops is said to be the infinite while loop, when we give the condition in such a way so that it never returns false, then the loops becomes infinite and repeats itself indefinitely.
In computer programming, loops are used to repeat a block of code. For example, when you are displaying number from 1 to 100 you may want set the value of a variable to 1 and display it 100 times, increasing its value by 1 on each loop iteration. When you know exactly how many times you want to loop through a block of code, use the for loop instead of a while loop. A for loop is a repetition control structure that allows you to efficiently write a loop that needs to execute a specific number of times.
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