명품 C++ 6장 연습문제 - 실습 문제

1.

(1)

#include <iostream>
using namespace std;

int add(int a[], int n) {
    int sum = 0;
    for (int i = 0; i < n; i++) sum += a[i];
    return sum;
}

int add(int a[], int n, int b[]) {
    int sum = 0;
    for (int i = 0; i < n; i++) sum += a[i] + b[i];
    return sum;
}

int main() {
    int a[] = {1, 2, 3, 4, 5};
    int b[] = {6, 7, 8, 9, 10};
    int c = add(a, 5);
    int d = add(a, 5, b);
    cout << c << endl;
    cout << d << endl;
}

(2)

#include <iostream>
using namespace std;

int add(int a[], int n, int b[] = nullptr) {
    int sum = 0;
    for (int i = 0; i < n; i++) {
        sum += a[i];
        if (b != nullptr) sum += b[i];
    }
    return sum;
}

int main() {
    int a[] = {1, 2, 3, 4, 5};
    int b[] = {6, 7, 8, 9, 10};
    int c = add(a, 5);
    int d = add(a, 5, b);
    cout << c << endl;
    cout << d << endl;
}

2.

(1)

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

class Person {
    int id;
    double weight;
    string name;
public:
    Person() {
        id = 1;
        name = "Grace";
        weight = 20.5;
    }
    Person(int id, string name) {
        this->id = id;
        this->name = name;
        weight = 20.5;
    }
    Person(int id, string name, double weight) {
        this->id = id;
        this->name = name;
        this->weight = weight;
    }
    void show() { cout << id << ' ' << weight << ' ' << name << endl; }
};

int main() {
    Person grace, ashley(2, "Ashley"), helen(3, "Helen", 32.5);
    grace.show();
    ashley.show();
    helen.show();
}

(2)

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

class Person {
    int id;
    double weight;
    string name;
public:
    Person(int id = 1, string name = "Grace", double weight = 20.5) {
        this->id = id;
        this->name = name;
        this->weight = weight;
    }
    void show() { cout << id << ' ' << weight << ' ' << name << endl; }
};

int main() {
    Person grace, ashley(2, "Ashley"), helen(3, "Helen", 32.5);
    grace.show();
    ashley.show();
    helen.show();
}

3.

(1)

#include <iostream>
using namespace std;

int big(int a, int b) {
    if (a < b) a = b;
    if (a > 100) return 100;
    else return a;
}

int big(int a, int b, int max) {
    if (a < b) a = b;
    if (a > max) return max;
    else return a;
}

int main() {
    int x = big(3, 5);
    int y = big(300, 60);
    int z = big(30, 60, 50);
    cout << x << ' ' << y << ' ' << z << endl;
}

(2)

#include <iostream>
using namespace std;

int big(int a, int b, int max = 100) {
    if (a < b) a = b;
    if (a > max) return max;
    else return a;
}

int main() {
    int x = big(3, 5);
    int y = big(300, 60);
    int z = big(30, 60, 50);
    cout << x << ' ' << y << ' ' << z << endl;
}

4.

#include <iostream>
using namespace std;

class MyVector {
    int *mem;
    int size;
public:
    MyVector(int n = 100, int val = 0);
    ~MyVector() { delete[] mem; }
    void show() {
        for (int i = 0; i < size; i++) cout << mem[i];
        cout << endl;
    }
};

MyVector::MyVector(int n, int val) {
    mem = new int[n];
    size = n;
    for (int i = 0; i < size; i++) mem[i] = val;
}

int main() {
    MyVector a;
    MyVector b(50, 1);
    a.show();
    b.show();
}

5.

#include <iostream>
using namespace std;

class ArrayUtility {
public:
    static void intToDouble(int source[], double dest[], int size) {
        for (int i = 0; i < size; i++) dest[i] = (double)source[i];
    }
    static void doubleToInt(double source[], int dest[], int size) {
        for (int i = 0; i < size; i++) dest[i] = (int)source[i];
    }
};

int main() {
    int x[] = {1, 2, 3, 4, 5};
    double y[5];
    double z[] = {9.9, 8.8, 7.7, 6.6, 5.6};

    ArrayUtility::intToDouble(x, y, 5);
    for (int i = 0; i < 5; i++) cout << y[i] << ' ';
    cout << endl;

    ArrayUtility::doubleToInt(z, x, 5);
    for (int i = 0; i < 5; i++) cout << x[i] << ' ';
    cout << endl;
}

6.

#include <iostream>
using namespace std;

class ArrayUtility2 {
public:
    static int *concat(int s1[], int s2[], int size) {
        int *arr = new int[size * 2];
        int n = 0;
        for (int i = 0; i < size; i++, n++) arr[n] = s1[i];
        for (int i = 0; i < size; i++, n++) arr[n] = s2[i];
        return arr;
    }
    static int *remove(int s1[], int s2[], int size, int &retSize) {
        int *arr = new int[size];
        bool t;
        for (int i = 0; i < size; i++)
        {
            t = true;
            for (int j = 0; j < size; j++)
            {
                if (s1[i] == s2[j])
                {
                    t = false;
                    break;
                }
            }
            if (t == true) {
                arr[retSize++] = s1[i];
            }
        }
        return arr;
    }
};

int main()
{
    cout << "정수를 5 개 입력하라. 배열 x에 삽입한다>>";
    int x[5];
    for (int i = 0; i < 5; i++) cin >> x[i];
    cout << "정수를 5 개 입력하라. 배열 y에 삽입한다>>";
    int y[5];
    for (int i = 0; i < 5; i++) cin >> y[i];

    cout << "합친 정수 배열을 출력한다" << endl;
    int *arr = ArrayUtility2::concat(x, y, 5);
    for (int i = 0; i < 10; i++) cout << arr[i] << ' ';
    cout << endl;
    delete[] arr;

    int size = 0;
    arr = ArrayUtility2::remove(x, y, 5, size);
    cout << "배열 x[]에서 y[]를 뺀 결과를 출력한다. 개수는 " << size << endl;
    for (int i = 0; i < size; i++) cout << arr[i] << ' ';
    cout << endl;
    delete[] arr;
}

7.

#include <iostream>
#include <cstdlib>
#include <ctime>
using namespace std;

class Random {
public:
    static void seed() { srand((unsigned)time(0)); }
    static int nextInt(int min = 0, int max = 32767) {
        return (rand() % (max - min + 1)) + min;
    }
    static char nextAlphabet() {
        int r = rand() % 52;
        if (r < 26) return 'a' + r;
        else return 'A' + r - 26;
    }
    static double nextDouble() {
        return rand() / 32767.;
    }
};

int main()
{
    Random::seed();
    cout << "1에서 100까지 랜덤한 정수 10개를 출력합니다" << endl;
    for (int i = 0; i < 10; i++) cout << Random::nextInt(1, 100) << ' ';
    cout << endl;

    cout << "알파벳을 랜덤하게 10개를 출력합니다" << endl;
    for (int i = 0; i < 10; i++) cout << Random::nextAlphabet() << ' ';
    cout << endl;

    cout << "랜덤한 실수를 10개를 출력합니다" << endl;
    for (int i = 0; i < 5; i++) cout << Random::nextDouble() << ' ';
    cout << endl;
    for (int i = 0; i < 5; i++) cout << Random::nextDouble() << ' ';
    cout << endl;
}

8.

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

class Trace {
public:
    static int max, num;
    static string trace[100][2];
    static void put(string tag, string ifo) {
        if (max > num) {
            trace[num][0] = tag;
            trace[num++][1] = ifo;
        }
    }
    static void print(string tag = "all") {
        if (tag == "all") {
            cout << "----- 모든 Trace 정보를 출력합니다. -----" << endl;
            for (int i = 0; i < num; i++) {
                cout << trace[i][0] << ":" << trace[i][1] << endl;
            }
        }
        else {
            cout << "----- " << tag << "태그의 Trace 정보를 출력합니다. -----" << endl;
            for (int i = 0; i < num; i++) {
                if (trace[i][0] == tag) {
                    cout << trace[i][0] << ":" << trace[i][1] << endl;
                }
            }
        }
    }
};

int Trace::max = 100;
int Trace::num = 0;
string Trace::trace[100][2] = {};

void f() {
    int a, b, c;
    cout << "두 개의 정수를 입력하세요>>";
    cin >> a >> b;
    Trace::put("f()", "정수를 입력 받았음");
    c = a + b;
    Trace::put("f()", "합 계산");
    cout << "합은 " << c << endl;
}

int main() {
    Trace::put("main()", "프로그램 시작합니다");
    f();
    Trace::put("main()", "종료");

    Trace::print("f()");
    Trace::print();
}

9.

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

class Board {
public:
    static string text[100];
    static int num;
    static void add(string t) { text[num++] = t; }
    static void print() {
        cout << "************* 게시판입니다. *************" << endl;
        for (int i = 0; i < num; i++) {
            cout << i << ": " << text[i] << endl;
        }
        cout << endl;
    }
};

string Board::text[100] = {};
int Board::num = 0;

int main()
{
    Board::add("중간고사는 감독 없는 자율 시험입니다.");
    Board::add("코딩 라운지 많이 이용해 주세요.");
    Board::print();
    Board::add("진소린 학생이 경진대회 입상하였습니다. 축하해주세요");
    Board::print();
}