Printing random lines from file C++

Printing random lines from file in C++ program is given below:

#include <iostream>
#include <fstream>
#include <string>
#include <windows.h>
using namespace std;

int main(){
ofstream os("a.txt");
for (int i = 0; i<=999; i++){
os << i << endl;
}
os.close();

ifstream is("a.txt");

char c;
string line;
while (!is.eof()){
while (c != '\n'){
is.seekg(rand()%1000);
c = is.get();
}
getline(is,line);
cout << line << endl; //Printing lines randomly from file.
c = '0';
Sleep(300);
}
return 0;
}


Though lines are being printed randomly but there is repetition.

Copy one file to another file C++

'Copy one file to another file in C++' program is given below.

You have to write copy c:/source.txt c:/destination.txt to copy contents of file source.txt to destination.txt.

#include <iostream>

#include <string>

#include <fstream>

using namespace std;

void Write(string, string);

int main(){

cout << "Write: copy srcfile destfile.cpp\nYou can give complete path as well.\n\n";

string s1, s2, s3;

cin >> s1 >> s2 >> s3;

if (strcmp(s1.c_str(),"copy") != 0){

cout << s1 << " is not a valid command. Only valid command for this program is copy." << endl;

}

Write(s2,s3);

return 0;

}

void Write(string s1, string s2){

char line[100];

ifstream is(s1.c_str());

ofstream os(s2.c_str());

if (is.is_open() && os.is_open()){

while (!is.eof()){

is.getline(line,100,'\n');

os << line << endl;

}

}

else{

if (!is.is_open()){

cout << endl << s1 <<" couldn't be opened. Creat and write something in a.txt, and try again." << endl;

}

else{

cout << endl << s2 <<" couldn't be opened. Creat and write something in a.txt, and try again." << endl;

}

}

}

Visit a simpler program:

Copy contents of One File to another C++

Copy contents of One File to another C++

'Copy file in C++' program is given below.

Copies content of file 'a' to file 'b'.

#include <iostream>

#include <fstream>

using namespace std;

int main(){

char line[100];

ifstream is("a.txt");

ofstream os("b.txt");

if (is.is_open()){

while (!is.eof()){

is.getline(line,100,'\n');

os << line << endl;

}

}

else{

cout << "a.txt couldn't be opened. Creat and write something in a.txt, and try again." << endl;

}

return 0;

}

See a better program:
Copy one file to another file C++

Finding a word from File C++

#include <iostream>
#include <fstream>
using namespace std;

int main(){
ofstream os("test.txt");
os << "1. Hi." << endl <<"2. By mom!" << endl << endl << "4. YES I did it." << endl << "5. I'm fine." << endl << "6. I'm writing different lines to the file, OK?";

os.close();

cout << "My file contains following data:\n";
cout << "1. Hi." << endl <<"2. By mom!" << endl << endl << "4. YES I did it." << endl << "5. I'm fine." << endl << "6. I'm writing different lines to the file, OK?";

cout << "\n\nEnter a word to find from it: ";
char word[50]; cin.getline(word,50,'\n');

//Calculating number of characters in word.
for ( int sizeOfWord = 0; word[sizeOfWord]!='\0'; sizeOfWord++);

//searching the word.
ifstream is("test.txt");

char sentence[200];
int line_no = 1;
int i = 0;
bool found = false;
while (!is.eof()){
is.getline(sentence,200,'\n');

for (int j = 0; sentence[j]!='\0'; j++){
if (sentence[j] == word[i]){
++i;
}
else{
i = 0;
}
if (i >= sizeOfWord){
cout << "Found at line: " << line_no << endl;
found = true;
}
}

line_no++;
}
if (!found){
cout << "NOT found." << endl;
}
return 0;
}

Reading Random lines from a text file C++

Calculate Time of program C++

Time in C++:
Following program calculates time of program execution in C++:

 #include <iostream>  
 #include <ctime>  
 #include <windows.h>  
 using namespace std;  
   
 int main(){  
      double start_time = clock();  
      Beep(500,1000); //BEEP FOR 1 SECOND will be produced. //YOUR CODE HERE.  
      double end_time = clock();  
        
   
      double time_taken = end_time - start_time;  
      double time_taken_in_seconds = time_taken/CLOCKS_PER_SEC;  
   
      cout << "Time taken during program execution is " << time_taken_in_seconds << " Second(s)"<< endl;  
        
      return 0;  
 }  

Sorting Linked List C++

'Sorting linked list in ascending order' program is given below:


#include <iostream>
using namespace std;
/////////////////////////////////////////////////////////////////////////////////////////////
struct node{
int data;
node *next;
};
/////////////////////////////////////////////////////////////////////////////////////////////
/////////////////////////////////////////////////////////////////////////////////////////////
class ll{
public:
ll();
void insert();
void print();
private:
node *head, *tail;
};
/////////////1////////////////////////////////////////////////////////////////////////////////
ll::ll(){
head = tail = 0;
}
/////////////////////////////////////////////////////////////////////////////////////////////
void ll::insert(){
node *temp = new node;
temp->next = NULL;
cout << "Id: ";  cin >> temp->data;
if (head == 0 && tail == 0){
head = temp;
tail = temp;
}
else{
if (temp->data <= head->data){
//Insert at head
temp->next = head;
head = temp;
}
else{
if (temp->data >= tail->data){
//insert at tail
tail->next = temp;
tail = temp;
}
else{// Insert some where in the middle.
node *p = head;
while (temp->data > p->data){//finding where to insert.
p = p->next;
}
//we've to insert at node before p.
//so
for (node *b = head; b->next != p; b = b->next);
//insert after bth node.
temp->next = b->next;
b->next = temp;
}
}
}
}
/////////////////////////////////////////////////////////////////////////////////////////////
void ll::print(){
for (node *p = head; p!=NULL; p=p->next){
cout << p->data << endl;
}
}
/////////////////////////////////////////////////////////////////////////////////////////////
//*******************************************************************************************
int main(){
ll o;
cout << "Do you want to insert? (y/n)  "; char opt; cin >> opt;

while (opt == 'y' || opt == 'Y'){
o.insert();
cout << "Do you want to insert? (y/n)  "; cin >> opt;
}

o.print();

return 0;
}
//*******************************************************************************************

Wacmian Numbers program C++

#include <iostream>
#include <cmath>
using namespace std;

int getInt(char);

int main(){
long int sum[100] = {0};
int u = 0;
char a[100] = "";
cout << "WACMIAN Number: "; cin >> a;

while (a[0]!='#' || a[1] != '\0'){


if (a[0] != '#' || a[1] != '\0'){

for (int j = 0; a[j]!= '\0'; j++);
j--;

for (int i = j, base = 0; i >= 0; i--, base++){
sum[u] += getInt(a[i])*pow(6,base);
}
if (a[0] != '#')
u++;
}
cout << "WACMIAN Number: "; cin >> a;
}

cout << endl << "OUTPUT:\n";
for (int i =0; i <= u; i++){
if (a[0] == '#' && sum[i] == 0 && i==u)
break;
cout << sum[i] << endl;
}


return 0;
}

int getInt(char u){
switch (u){
case '%':
return 0;
case ')':
return 1;
case '~':
return 2;
case '@':
return 3;
case '?':
return 4;
case '\\':
return 5;
case '$':
return -1;
default:
cout << "Wrong input." << endl;
exit(0);
}
}

Sound in C++

#include <windows.h>

int main()
{
    Beep(1568, 200);
    Beep(1568, 200);
    Beep(1568, 200);
    Beep(1245, 1000);
    Beep(1397, 200);
    Beep(1397, 200);
    Beep(1397, 200);
    Beep(1175, 1000);
   
    return 0;
}
/////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////

#include <iostream.h>
#include <windows.h>

void scale(void)
{ Beep(523,400); // 523 hertz (C5) for 400 milliseconds
 Beep(587,400);
 Beep(659,400);
 Beep(698,400);
 Beep(784,400);
 Beep(698,400);
 Beep(659,400);
 Beep(587,400);
 Beep(523,400);
}


int main()
{

 scale();
 cout << "Scale completed.\n";
 
 return 0;
}

/////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////

Reading Writing from Linked List C++

#include <iostream>
#include <fstream>
#include <fstream>
using namespace std;



struct link{
int data;
link* next;
};

class linkedList{
public:
linkedList();
void addItem(int);
void print(void);
private:
link* head;
link* tail;
};

linkedList::linkedList(){
head = tail = NULL;
}

void linkedList::addItem(int n){
link* temp = new link;
temp->data = n;
temp->next = 0;

if (head == 0 && tail == 0){
head = temp;
tail = temp;
}
else{
tail->next = temp;
tail = temp;
}
ofstream os("linkedList.txt", ios::out | ios::app);
os << "data: " << temp->data << endl;
os.close();
}

void linkedList::print(){
for (link* p = head; p != NULL; p = p->next){
cout << p->data << endl;
}
}

int main(){
ofstream os("linkedList.txt");
os.close();

int n;  
linkedList ll;
cout << "Enter number to insert: (-1 to print): "; cin >> n;

while (n!=-1){
ll.addItem(n);
cout << "Enter number to insert: (-1 to print): "; cin >> n;
}
   
ll.print();

cout << "Linked List has been written in the file and has been printed\nNow printing link List's data using file." << endl;

//READING LINKED LIST FROM FILE.
//////////////
// linkedList LL;
char str;
ifstream is;
is.open("linkedList.txt");
while (is){
is.get(str);
cout << str;
}
is.close();
return 0;
}

Inheritance example C++

#include <iostream>
using namespace std;

class cc{

};

class m:  public cc{
public:
void f(){
cout << "m" << endl << endl;
}
};
class l:  public cc{
public:
void f(){
cout << "l" << endl << endl;
}
};
class v:  public cc{
public:
void f(){
cout << "v" << endl << endl;
}
};

class ll: public m, public l, public v{
};

int main(){
ll *p = new ll;

p->m::f();
return 0;
}