// CPP Program to demonstrate the implementation in Map
// divyansh mishra --> divyanshmishra101010
#include <iostream>
#include <iterator>
#include <map>
using namespace std;

int main()
{

	// empty map container
	map<int, int> gquiz1;

	// insert elements in random order
	gquiz1.insert(pair<int, int>(1, 40));
	gquiz1.insert(pair<int, int>(2, 30));
	gquiz1.insert(pair<int, int>(3, 60));
	gquiz1.insert(pair<int, int>(4, 20));
	gquiz1.insert(pair<int, int>(5, 50));
	gquiz1.insert(pair<int, int>(6, 1000));

	// another way of inserting a value in a map
	gquiz1[7] = 10;

	// printing map gquiz1
	map<int, int>::iterator itr;
	cout << "\nThe map gquiz1 is : \n";
	cout << "\tKEY\tELEMENT\n";
	for (itr = gquiz1.begin(); itr != gquiz1.end(); ++itr) {
		cout << '\t' << itr->first << '\t' << itr->second
			<< '\n';
	}
	cout << endl;

	// assigning the elements from gquiz1 to gquiz2
	map<int, int> gquiz2(gquiz1.begin(), gquiz1.end());

	// print all elements of the map gquiz2
	cout << "\nThe map gquiz2 after"
		<< " assign from gquiz1 is : \n";
	cout << "\tKEY\tELEMENT\n";
	for (itr = gquiz2.begin(); itr != gquiz2.end(); ++itr) {
		cout << '\t' << itr->first << '\t' << itr->second
			<< '\n';
	}
	cout << endl;

	// remove all elements up to
	// element with key=3 in gquiz2
	cout << "\ngquiz2 after removal of"
			" elements less than key=3 : \n";
	cout << "\tKEY\tELEMENT\n";
	gquiz2.erase(gquiz2.begin(), gquiz2.find(3));
	for (itr = gquiz2.begin(); itr != gquiz2.end(); ++itr) {
		cout << '\t' << itr->first << '\t' << itr->second
			<< '\n';
	}

	// remove all elements with key = 4
	int num;
	num = gquiz2.erase(4);
	cout << "\ngquiz2.erase(4) : ";
	cout << num << " removed \n";
	cout << "\tKEY\tELEMENT\n";
	for (itr = gquiz2.begin(); itr != gquiz2.end(); ++itr) {
		cout << '\t' << itr->first << '\t' << itr->second
			<< '\n';
	}

	cout << endl;

	// lower bound and upper bound for map gquiz1 key = 5
	cout << "gquiz1.lower_bound(5) : "
		<< "\tKEY = ";
	cout << gquiz1.lower_bound(5)->first << '\t';
	cout << "\tELEMENT = " << gquiz1.lower_bound(5)->second
		<< endl;
	cout << "gquiz1.upper_bound(5) : "
		<< "\tKEY = ";
	cout << gquiz1.upper_bound(5)->first << '\t';
	cout << "\tELEMENT = " << gquiz1.upper_bound(5)->second
		<< endl;

	return 0;
}
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#include <iostream>
#include <string>
using namespace std;

int main() 
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    string name;
    cout << "Enter name:";
    getline (cin, name);
    cout << "Hello " << name;
    return 0;
}

About C++

C++ is a widely used middle-level programming language.

  • Supports different platforms like Windows, various Linux flavours, MacOS etc
  • C++ supports OOPS concepts like Inheritance, Polymorphism, Encapsulation and Abstraction.
  • Case-sensitive
  • C++ is a compiler based language
  • C++ supports structured programming language
  • C++ provides alot of inbuilt functions and also supports dynamic memory allocation.
  • Like C, C++ also allows you to play with memory using Pointers.

Syntax help

Loops

1. If-Else:

When ever you want to perform a set of operations based on a condition If-Else is used.

if(conditional-expression) {
   //code
}
else {
   //code
}

You can also use if-else for nested Ifs and If-Else-If ladder when multiple conditions are to be performed on a single variable.

2. Switch:

Switch is an alternative to If-Else-If ladder.

switch(conditional-expression){    
case value1:    
 // code    
 break;  // optional  
case value2:    
 // code    
 break;  // optional  
......    
    
default:     
 code to be executed when all the above cases are not matched;    
}

3. For:

For loop is used to iterate a set of statements based on a condition.

for(Initialization; Condition; Increment/decrement){  
  //code  
}

4. While:

While is also used to iterate a set of statements based on a condition. Usually while is preferred when number of iterations are not known in advance.

while (condition) {  
// code 
}

5. Do-While:

Do-while is also used to iterate a set of statements based on a condition. It is mostly used when you need to execute the statements atleast once.

do {  
 // code 
} while (condition);

Functions

Function is a sub-routine which contains set of statements. Usually functions are written when multiple calls are required to same set of statements which increases re-usuability and modularity. Function gets run only when it is called.

How to declare a Function:

return_type function_name(parameters);

How to call a Function:

function_name (parameters)

How to define a Function:

return_type function_name(parameters) {  
 // code
}