Vijay Krishnavanshi
Open Source Developer at KDE
string name = "Brice";
#include <iostream>
using namespace std;
int main()
{
string name("");
cout << "What is your name?" << endl;
cin >> name;
cout << "Hello " << name << ", how are you today?" << endl;
return 0;
}
#include <iostream>
using namespace std;
int main() // Every C++ programs start by running this function
{
cout << "Hello world!" << endl;
return0;
}
type functionName(arguments)
{
[...]
instructions;
[...]
return value;
}
int add(int a, int b)
{
int result;
result = a + b;
return result;
}
int main()
{
cout << "Write a first integer: "; cin >> int1;
cout << "Write a second integer: "; cin >> int2;
int int3 = add(int1, int2);
cout << int1 << "+" << int2 << "=" << int3 << endl;
return 0;
}
void sayHello()
{
cout << "Hello!" << endl;
}
int addTwo(int a)
{
a = a + 2;
return a;
}
int main()
{
int number(6), result;
result = addTwo(number);
cout << "number=" << number << " and result=" << result << endl;
return 0;
}
// number = 6
// result = 8
int addTwo(int& a)
{
a = a + 2;
return a;
}
int main()
{
int number(6), result;
result = addTwo(number);
cout << "number=" << number << " and result=" << result << endl;
return 0;
}
// number = 8
// result = 8
void copyBook(string text) // long to copy
{}
void copyBook2(string& text) // can modify original text
{}
void copyBook3(string const& text) // fast copy and read-only
{}
#ifndef MATH_H_INCLUDED // Ensure to include this file only once
#define MATH_H_INCLUDED // in the compilation process
// Add 2 numbers and return their sum
int add(int a, int b);
// Take number as argument and return number + 2
int addTwo(int a);
#endif
#include "math.h" // Link the header
int add(int a, int b)
{
int result;
result = a + b;
return result;
}
int addTwo(int a)
{
a = a + 2;
return a;
}
#include <iostream>
#include "math.h" // Link the functions of math files
int main()
{
int number;
cout << "Enter an integer: "; cin >> number;
addTwo(number);
cout << "Your number + 2 = " << number << endl;
return 0;
}
type name[size];
int const numberOfClasses(5); // The size of the array is known
string classes[numberOfClasses];
string classes[5];
classes[0] = "B1"; // Arrays starts with the index 0
classes[1] = "B2";
classes[2] = "B3";
classes[3] = "M1";
classes[4] = "M2";
cout << "The class for B2 students is: " << classes[1] << endl;
for(int i=0; i<numberOfClasses; i++) // numberOfClasses = 5
{
cout << classes[i] << endl;
}
#include <vector> // Do not forget to include the "vector" library!
vector<type> name(initialSize, defaultValue);
vector<double> scores;
vector<string> students(5);
vector<string> teachers(10, "no name");
vector<string> students(5, "no name");
students[0] = "Justin BIEBER";
students[1] = "Bruce LEE";
students[2] = "Jack JOHNS";
cout << students[1] << endl; // Display Bruce LEE
for (int i=0; i<students.size(); i++) //size() returns the array size
{
cout << students[i] << endl;
} // Display all the students names
vector<double> scores; // Declare an empty array
scores.push_back(18);
scores.push_back(11);
for(int i=0; i<scores.size(); i++) { cout << scores[i] << endl; }
18
11
vector<double> scores; // Declare an empty array
scores.push_back(18); // Add the value 18
scores.push_back(11); // Add the value 11
scores.pop_back(); // Remove the last value of the array
for(int i=0; i<scores.size(); i++) { cout << scores[i] << endl; }
18
type name[sizeA][sizeB]...[sizeN];
int const sizeX(5);
int const sizeY(4);
int scores[sizeX][sizeY];
int myAge(30);
cout << "The value of myAge is: " << myAge << endl;
cout << "The address of myAge is: " << &myAge << endl;
A pointer is a variable containing the address of another variable
type *name;
int *p1;
double *p2;
sting *p3;
unsigned int *p4;
vector<string> *p5;
type *name(0);
int *p1(0);
int myAge(30);
int *myPointer(0);
myPointer = &myAge;
cout << myPointer << endl; // Output 0x1ab23c4d for example
cout << *myPointer << endl; // Output 30
By Vijay Krishnavanshi