[강좌#3] Expressions and Interactivity

- statc_cast<int>

- const

---

cout 기본 입출력

http://young_0620.blog.me/50189720699

- setw(x)

- fixed

- setprecision(x)

- showpoint

- left, right

// This program illustrates the use of the left and right manipulators.

#include <iostream>

#include <iomanip>        // Needed to use stream manipulators

#include <string>

using namespace std;

int main()

{  

string month1 = "January",

  month2 = "February",

  month3 = "March";

int days1 = 31,

   days2 = 28,

days3 = 31;

double high1 = 22.6,

  high2 = 37.4,

  high3 = 53.9;

cout << fixed << showpoint << setprecision(1);

cout << "Month        Days    High\n";

cout << left  << setw(12) << month1 

<< right << setw(4)  << days1 << setw(9) << high1 << endl;

cout << left  << setw(12) << month2 

<< right << setw(4)  << days2 << setw(9) << high2 << endl;

cout << left  << setw(12) << month3 

    << right << setw(4)  << days3 << setw(9) << high3 << endl;

   return 0;

}

#include <iomanip> 

cout.setf(ios :: fixed);

cout.setf(ios :: showpoint);

cout.precision(3);

 

세개는 붙어다니는 하나의 세트라고 봐도 좋을 것 같다.

 

cout.setf(ios :: fixed); 가 뜻하는 것은 고정 소수점 출력,

cout.setf(ios :: showpoint); 는 소수점을 보여준다는 것,

cout.precision(3);는 소수점 이하 3자리를 뜻한다.

---

cin

- getline(cin, string)

#include <iostream>

#include <string>

using namespace std;

int main()

{

string name;

string city;

cout << "Please enter your name: ";

getline(cin, name);

cout << "Enter the city you live in: ";

getline(cin, city);

cout << "Hello, " << name << endl; 

cout << "You live in " << city << endl;

return 0;

}

- cin.get(x)

---

String

- strcpy(x,y)

---

#include <cmath>

- sqrt()

---

#include <cstdlib>

- rand()

- srand()

---

#include <fstream>

[파일 쓰기]

#include <iostream>

#include <fstream>               // Needed to use files

using namespace std;

int main()

{

ofstream outputFile;

outputFile.open("demofile.txt");

cout << "Now writing information to the file.\n";

// Write 3 great names to the file

outputFile << "Bach\n";

outputFile << "Beethoven\n";

outputFile << "Mozart\n";

// Close the file

outputFile.close();

cout << "Done.\n";

return 0;

}

[파일 읽기]

// This program uses the >> operator to read information from a file.

#include <iostream>

#include <fstream>                 // Needed to use files

#include <string>                    

using namespace std;

int main()

{

ifstream inFile;

string name;

inFile.open("demofile.txt");

cout << "Reading information from the file.\n\n";

inFile >> name;                // Read name 1 from the file

cout << name << endl;          // Display name 1

inFile >> name;                // Read name 2 from the file

cout << name << endl;          // Display name 2

inFile >> name;                // Read name 3 from the file

cout << name << endl;          // Display name 3

inFile.close();                // Close the file

cout << "\nDone.\n";

return 0;

}