Skip to main content

Useful C++ code snippets


Setting up  Precision to given decimal point 
“std:setprecision()”  method used along with  “std:fixed” provides precision of 
outputting floating point numbers correct to decimal numbers mentioned in the parameter 
of the setprecision method.
header file
#include <iomanip>
std:setprecision() defined no of digits in number. Without using std:fixed() method setprecision()  will   limit whole numbers digits to given precision.
In order to print precision of decimal point both setprecision() and fixed() method using before printing values,
code snippet :
 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
17
18
19
20
21
22
// setprecision example

#include <iostream>     // std::cout, std::fixed
#include <iomanip>      // std::setprecision

int main(){

     double   doubeleValue =3.34535 ;

     std::cout <<  std::setprecision(4) ;
     std::cout <<  doubeleValue<< '\n';
      // Output : 3.345  -without fixed


      std::cout << std::fixed;
      std::cout <<  doubeleValue<< '\n';// Output : 3.3453

     std::cout <<  std::setprecision(2) <<std::fixed<< doubeleValue<< '\n';
      // Output : 3.34

    return 0;
} 



Getting input from Terminal / CommandLine


 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
// setprecision example

#include <iostream>
#include <string>

using namespace std;

int main(){

    int getInt;
    std::cout << "Get Int : " ;

    cin >> getInt  ;
    std::cout << "int " << getInt<<'\n';
    // using cin >> you can get any primative data type

    /*  to get whole line as string use string and getline method
    */
    string str;
    std::cout << "String :" ;
    std::getline(std::cin,str);
    std::cout << str << '\n';

    return 0;
}


Getting multiple numeric values in same Line of Terminal/CMD
 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
17
18
19
20
21
#include <iostream>
#include <sstream>
#include <iterator>
#include <string>
#include <vector>

int main() 
{
    std::string s;

    std::getline( std::cin, s );

    std::istringstream is( s );

    std::vector<int> v( ( std::istream_iterator<int>( is ) ), std::istream_iterator<int>() );

    for ( int x : v) std::cout << x << ' ';
    std::cout << std::endl;

    return 0;
}

Getting the power of value
 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
/* pow example */
#include <stdio.h>      /* printf */
#include <math.h>       /* pow */

int main ()
{
  printf ("7 ^ 3 = %f\n", pow (7.0, 3.0) );
  printf ("4.73 ^ 12 = %f\n", pow (4.73, 12.0) );
  printf ("32.01 ^ 1.54 = %f\n", pow (32.01, 1.54) );
  return 0;
}

Reading a text file
 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
// ios::exceptions
#include <iostream>
#include <fstream>
using namespace std;

void do_something_with(char ch) {} // Process the character 

int main () {
  ifstream file;
  file.exceptions ( ifstream::badbit ); // No need to check failbit
  try {
    file.open ("test.txt");
    char ch;
    while (file.get(ch)) do_something_with(ch);
    // for line-oriented input use file.getline(s)
  }
  catch (const ifstream::failure& e) {
    cout << "Exception opening/reading file";
  }

  file.close();

  return 0;
}

Writing a text file
 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
// writing on a text file
#include <iostream>
#include <fstream>
using namespace std;

int main () {
  ofstream myfile ("example.txt");
  if (myfile.is_open())
  {
    myfile << "This is a line.\n";
    myfile << "This is another line.\n";
    myfile.close();
  }
  else cout << "Unable to open file";
  return 0;
}

Calculating the run time of given code
 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
// writing on a text file
#include <iostream>
#include <fstream>
using namespace std;

int main () {
  ofstream myfile ("example.txt");
  if (myfile.is_open())
  {
    myfile << "This is a line.\n";
    myfile << "This is another line.\n";
    myfile.close();
  }
  else cout << "Unable to open file";
  return 0;
}



 
Labels:

Comments

Post a Comment

Popular posts from this blog

How to proceed once you selected an organization in GSoC

How to proceed once you selected an organization in GSoC? In GSoC, each step you follow is very critical to get selected as a GSoC intern.For each step difficult increase and you have been specified what kind of specialize domain chose to select.Here is my experience in GSoC after I selected an organization. Once you selected an organization, you have done research to select a project which best suits your skills and time availability. First, find present and past project ideas given by the organization and note the projects you prefer. Then go through the mail achieves and fine mails about selected project ideas. From those mail archives, you can get a better understanding of those projects and what kind of future improvement they require. After that try to build an implementation for selected project and create a repository for that.then send a mail to selected organization mailing list stating your interest and showcase the what you have implemented. also, the...
Post a Comment
Read more

My IEEE Story

As a proud student member of IEEE. I would like to say IEEE is a great place to build your professional life and gain experiences.IEEE is a great place for those students who are curious to gather knowledge .not the only knowledge, programmes held by IEEE are based on fun and enjoyment too.  IEEE Student/Young professional / Women in engineering Congress 2017 can be mention as an example for such events. It was one of the best events I participated in my undergraduate life.lots of volunteers were participated in that. there I was able to build up a lot of friendships and relationships with the volunteers all around the country .we share those relations even after the Congress which help us to share our ideas and knowledge .that help me to solve problems which are impossible for me to solve alone. I got this golden chance only because of IEEE .i will always be thankful to IEEE for giving us such opportunities. Not only that, the fun,  glamour,  education,  ...
Post a Comment
Read more

Essentials things to do after installing Ubuntu 18.04

Essentials things to do after installing Ubuntu 18.04 Those steps will smooth your experience with Ubuntu 18.04 Bionic Beaver 1. Update the system To update Ubuntu 18.04, press Super Key (Windows Key) to launch the Activity Overview and look for Software Updater. Run it to check for updates. Alternatively  user terminal to update and upgrade ( Use Ctrl+Alt+T): $ sudo apt update && sudo apt upgrade 2. Enable additional repositories for more software Go to Activity Overview by pressing Super Key (Windows key), and search for Software & Updates: Under the Ubuntu Software tab, make sure you have checked all of the Main, Universe, Restricted and Multiverse repository checked. Now move to the Other Software tab, check the option of Canonical Partners 3. Install media codecs Using terminal ( Use Ctrl+Alt+T):  $ sudo apt install ubuntu-restricted-extras 4. Prolong your battery and prevent overheating Let’s move on to prevent ov...
Post a Comment
Read more