코드 노트

1.

#include <iostream>
using namespace std;

int main() {
	int count = 0;
	int ch;
	while ((ch = cin.get()) != EOF) {
		if (ch == 'a') count++;
		else if (ch == '\n') break;
	}
	cout << "a 문자는 총 " << count << "개 입니다." << endl;
}

2.

#include <iostream>
using namespace std;

int main() {
	int count = 0;
	char ch;
	while (true) {
		cin.get(ch);
		if (ch == EOF) break;
		else if (ch == ' ') count++;
		else if (ch == '\n') break;
	}
	cout << "\' \' 문자는 총 " << count << "개 입니다." << endl;
}

3.

#include <iostream>
using namespace std;

int main() {
	int ch;
	cin.ignore(100, ';');
	while ((ch = cin.get()) != EOF) {
		cout.put(ch);
		if (ch == '\n') {
			cin.ignore(100, ';');
		}
	}
}

4.

#include <iostream>
using namespace std;

int main() {
	int ch;
	while ((ch = cin.get()) != EOF) {
		if (ch == ';') {
			cin.ignore(100, '\n');
			cout.put('\n');
		}
		else cout.put(ch);
	}
}

5.

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

int main() {
	string cmd;
	while (true) {
		cout << "종료하려면 exit을 입력하세요 >> ";
		getline(cin, cmd);
		if (cmd == "exit") {
			cout << "프로그램을 종료합니다...." << endl;
			break;
		}
	}


}

6.

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

int main() {
	cout << left;
	cout << setw(15) << "Number";
	cout << setw(15) << "Square";
	cout << setw(15) << "Square Root" << endl;

	for (int i = 0; i <= 45; i += 5) {
		cout << setw(15) << setfill('_') << i;
		cout << setw(15) << setfill('_') << i * i;
		cout << setw(15) << setprecision(3) << setfill('_') << sqrt((double)i) << endl;
	}
}

7.

#include <iostream>
#include <string>
#include <cmath>
#include <cctype>
#include <iomanip>
using namespace std;


int main() {
	cout << "dec" << '\t' << "hexa" << '\t' << "char" << '\t';
	cout << "dec" << '\t' << "hexa" << '\t' << "char" << '\t';
	cout << "dec" << '\t' << "hexa" << '\t' << "char" << '\t';
	cout << "dec" << '\t' << "hexa" << '\t' << "char" << endl;

	cout << "---" << '\t' << "---" << "\t" << "---" << "\t";
	cout << "---" << '\t' << "---" << "\t" << "---" << '\t';
	cout << "---" << '\t' << "---" << "\t" << "---" << '\t';
	cout << "---" << '\t' << "---" << "\t" << "---" << endl;

	for (int i = 0; i < 128; i++) {
		cout << dec << i << '\t' << hex << i << '\t';
		cout << (isprint((char)i) ? (char)i : '.') << '\t';
		if (i % 4 == 3)
			cout << endl;
	}
}

8.

#include <iostream>
#include <string>
#include <cmath>
#include <cctype>
#include <iomanip>
using namespace std;


class Circle {
	string name;
	int radius;
public:
	Circle(int radius = 1, string name = "") {
		this->radius = radius;
		this->name = name;
	}
	friend istream& operator>> (istream& in, Circle& c);
	friend ostream& operator<<(ostream& out, Circle c);
};

istream& operator>> (istream& in, Circle& c) {
	cout << "반지름 >> ";
	in >> c.radius;
	cout << "이름 >> ";
	in >> c.name;
	return in;
}

ostream& operator<<(ostream& out, Circle c) {
	out << "(반지름" << c.radius << "인 " << c.name << ")";
	return out;
}


int main() {
	Circle d, w;
	cin >> d >> w;
	cout << d << w << endl;
}

9. 띄어쓰기 포함 -> getline(in, ph.address)

#include <iostream>
#include <string>
#include <cmath>
#include <cctype>
#include <iomanip>
using namespace std;

class Phone {
	string name;
	string telnum;
	string address;
public:
	Phone(string name = "", string telnum = "", string address = "") {
		this->name = name;
		this->telnum = telnum;
		this->address = address;
	}
	friend istream& operator>> (istream& in, Phone& ph);
	friend ostream& operator<< (ostream& out, Phone ph);
};

istream& operator>> (istream& in, Phone& ph) {
	cout << "이름:";
	getline(in, ph.name);
	cout << "전화번호:";
	getline(in, ph.telnum);
	cout << "주소:";
	getline(in, ph.address);
	return in;
}

ostream& operator<< (ostream& out, Phone ph) {
	cout << "(" << ph.name << "," << ph.telnum << "," << ph.address << ")";
	return out;
}

int main() {
	Phone girl, boy;
	cin >> girl >> boy;
	cout << girl << endl << boy << endl;
}

10

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



istream& prompt(istream& in) {
	cout << "암호?";
	return in;
}

int main() {
	string password;
	while (true) {
		cin >> prompt >> password;
		if (password == "C++") {
			cout << "login success!!" << endl;
			break;
		}
		else
			cout << "login fail. try again!!" << endl;
	}
}

11

#include <iostream>
using namespace std;

istream& pos(istream& in) {
	cout << "위치는? ";
	return in;
}

int main() {
	int x, y;
	cin >> pos >> x;
	cin >> pos >> y;
	cout << x << ',' << y << endl;
}