Convert Url to IP address in C++.

Convert Url to IP address in C++.


//Convert Url to IP address in C++.
#include <iostream>
#include <sys/types.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
#include <stdlib.h>
//#include<<errno.h>
#include <string.h>
#include <unistd.h>
#include <netdb.h>
#include <unistd.h>
#include <stdio.h>

using namespace std;

int hostname_to_ip(char * hostname , char* ip); // url to ip

int main(){
    char hn[] = "www.google.com";
    char *hostname = hn;
    char ip[100];
    hostname_to_ip(hostname, ip);
    printf("%s resolved to %s" , hostname , ip);
    return 0;
}

int hostname_to_ip(char * hostname , char* ip)
{
struct hostent *he;
struct in_addr **addr_list;
int i;

if ( (he = gethostbyname( hostname ) ) == NULL)
{
// get the host info
herror("gethostbyname");
return 1;
}

addr_list = (struct in_addr **) he->h_addr_list;

for(i = 0; addr_list[i] != NULL; i++)
{
//Return the first one;
strcpy(ip , inet_ntoa(*addr_list[i]) );
return 0;
}

return 1;
}

Multiply 2 Matrices of any order in C++

//Multiply 2 Matrices of any order in C++
#include <iostream>
using namespace std;

int main()
{
cout << "Size of Matrix A:";
int rows1, columns1;
cin>>rows1>>columns1;
//Initializing a 2-d dynamic array.
int ** m1 = new int *[rows1];

for (int i = 0; i<rows1; i++)
m1[i] = new int [columns1];

//Inputing Matrix.
cout << "Enter Matrix A\n";
for (int r = 0; r<rows1; r++)
for (int c = 0; c<columns1; c++)
cin>>m1[r][c];
//--------------------------------------
cout << "Size of Matrix B:";
int rows2, columns2;
cin>>rows2>>columns2;

int ** m2 = new int *[rows2];

for (i = 0; i<rows2; i++)
m2[i] = new int [columns2];

//Inputing Matrix.
cout << "Enter Matrix B\n";
for ( r = 0; r<rows2; r++)
for (int c = 0; c<columns2; c++)
cin>>m2[r][c];
//--------------------------------------

//Printing Matrix A.
cout << "\nA:\n";
for ( r = 0; r<rows1; r++)
{
for (int c = 0; c<columns1; c++)
cout << m1[r][c] << ' ';

cout << endl;
}

//Printing Matrix B.
cout << "\nB:\n";
for ( r = 0; r<rows2; r++)
{
for (int c = 0; c<columns2; c++)
cout << m2[r][c] << ' ';

cout << endl;
}


int result = 0;
//A*B

cout << endl <<endl << "A*B =";
for (int constR = 0; constR < rows1; constR++)
{
cout << endl;
for (int constC = 0; constC < columns2; constC++)//for Next element
{
result = 0;
r = 0;
for (int c = 0; r<rows2; r++,c++)//calculating each element
{
result +=  m1[constR][c] * m2[r][constC];
}
cout << result<< ' ';
}
}

return 0;
}

Get Desktop Path Dynamically in C++

This program automatically finds the path of desktop in C++.

#include <iostream>
#include <windows.h>
#include <tchar.h>
#include <shlobj.h> // for SHGetKnownFolderPath
using namespace std;

int _tmain() {
    PWSTR pPath = NULL; // this is always a wchar_t*

    // There is no Ansi (char*) version of this function so the TCHAR trick
    // doesn't work here
    HRESULT hr = SHGetKnownFolderPath( FOLDERID_Desktop,
                                       0,    // no flags
                                       NULL, // no tokens
                                       &pPath ); // note we're passing the address here

    if(SUCCEEDED(hr)) {
        wcout << L"Desktop path = " << pPath << endl;
        CoTaskMemFree(pPath); // free memory with correct deallocator function
    }

    return 0;
}

Get Desktop Path Dynamically in C++

This program automatically finds the path of desktop in C++.
#include "stdafx.h"
#include <iostream>
#include <Windows.h>
#include <tchar.h>
#include <shlobj.h> // for SHGetFolderPath

using namespace std;

int main(int argc, _TCHAR* argv[])
{
TCHAR path[_MAX_PATH] = _T(""); // must be _MAX_PATH in size

HRESULT hr = SHGetFolderPath(NULL, // no parent window
CSIDL_DESKTOP,
0,    // no flags
NULL, // no tokens
path);

if (SUCCEEDED(hr)) {
#ifdef _UNICODE
wcout << L"Desktop path = " << path << endl;
#else
cout << "Desktop path = " << path << endl;
#endif
}
}

How to Convert Int to String in C++

I've created my own function to convert an integer (int) to String in C++.

#include "stdafx.h"
#include <string>
#include <iostream>
#include <stack>

using namespace std;

string intToString(int no);

int main(int argc, _TCHAR* argv[])
{
cout << "These are all strings numbers" << endl;
for (int i = 0; i < 20; i++)
cout << intToString(i) << endl;
}

string intToString(int no){
string s = "";
string s2 = "";
if (no <= 9 && no >= 0){
char c = no + 48;
s += c;
return s;
}
else{
do{
char c = no % 10;
s += c + 48;
no /= 10;
} while (no != 0);
//Reverse string
for (int i = s.length() - 1; i >= 0; i--)
{
s2 += s[i];
}
return s2;
}
}

Built in Stack in C++ - STL

#include "stdafx.h"
#include <iostream>
#include <stack>

using namespace std;

int main(int argc, _TCHAR* argv[])
{
stack<int> st;
st.push(1);
cout << "Pushed: " << st.top() << endl;
st.push(2);
cout << "Pushed: " << st.top() << endl;
st.push(3);
cout << "Pushed: " << st.top() << endl << endl;
while (!st.empty())
{
cout << "Emptying..." << endl;
st.pop();
}
//cout << "Stack top now: " << st.top() << endl;
}

GCM - Greatest Common Multiple Program in C++

Program to calculate GCM ( Greatest Commmon Multiple ) in C++ is given below:

// GCM - Greateset Common Multiple program in C++
#include "stdafx.h" //COMMENT THIS LINE IF IT CAUSES ERROR
#include <iostream>

Typecasting in C++

Typecasting in C++ is shown below by typecasting an integer to a character.

//integer to character typecasting
#include <iostream>
using namespace std;

Get System Time and Date in C++

This program gets system time and date in C++.

//How to get system time in C++.
#include <iostream>
#include <ctime>