模範解答

＜演習１＞の解答例

import java.util.Scanner;

class Ensyu1201
{
public static void main(String[] args)
{
    Scanner sc = new Scanner(System.in);
    double radius;

    System.out.print("半径入力(実数値)--> ");
    radius = sc.nextDouble(); // 実数値を入力

    System.out.println(" 円周の長さ = " + 2.0*Math.PI*radius );
}
}

＜演習２＞の解答例

import java.util.Scanner;

class Ensyu1202
{
public static void main(String[] args)
{
    Scanner sc = new Scanner(System.in);
    double angle,rad;

    System.out.print("角度を入力(実数値)--> ");
    angle = sc.nextDouble(); // 実数値を入力

    rad = Math.PI*(angle/180.0); // ラジアン度数に変換
    System.out.println(" sin(" + angle + ") = " + Math.sin(rad) );
    System.out.println(" cos(" + angle + ") = " + Math.cos(rad) );
}
}

＜演習３＞の解答例

import java.util.Scanner;

class Ensyu1203
{
public static void main(String[] args)
{
    Scanner sc = new Scanner(System.in);
    int n;

    System.out.print("nを入力(整数値)--> ");
    n = sc.nextInt(); // 整数値を入力

    System.out.println(" 2の " + n + " 乗 = " + Math.pow(2,n) );

}
}

＜演習４＞の解答例

import java.util.Scanner;

class Ensyu1204
{
public static void main(String[] args)
{
    Scanner sc = new Scanner(System.in);
    int small,big,rnd;

    System.out.print("最小値を入力(整数値)--> ");
    small = sc.nextInt(); // 整数値を入力
    System.out.print("最大値を入力(整数値)--> ");
    big = sc.nextInt(); // 整数値を入力

    for(int i=0;i<100;i++){
    rnd = (int)(Math.random()*(big - small + 1)) + small;
      System.out.print(" " + rnd );
    }
}
}

＜演習５＞の解答例

import java.util.Scanner;

class Ensyu1205
{
public static void main(String[] args)
{
    Meibo [] mb = new Meibo[5];
    Scanner sc = new Scanner(System.in);

    for(int i=0;i<mb.length;i++){
      System.out.print("名前を入力--> ");
      String s = sc.next(); // 文字列を入力
      mb[i] = new Meibo( s );
    }

    for(int i=0;i<mb.length;i++){ // 名前を表示
      System.out.println(" 名前：" + mb[i].name );
    }
}
}

class Meibo
{
String name; // 名前

public Meibo( String s ){ // コンストラクタ
    name = new String( s );
}
}

＜演習６＞の解答例

class Ensyu1206
{
public static void main(String[] args)
{
    Point [] pt = new Point[5];

    pt[0] = new Point("名古屋", 688.7, 161.3 );
    pt[1] = new Point("大阪", 534.0, 103.5 );
    pt[2] = new Point("岡山", 356.1, 100.1 );
    pt[3] = new Point("広島", 193.6, 70.1 );
    pt[4] = new Point("北九州", 18.9, 14.5 );

    for(int i=0;i<5;i++) show( pt[i] );
}
// 内容を表示
public static void show( Point p ){
    System.out.println( p.name + " [" + p.x + ", " + p.y + "]" );
}
}

class Point
{
String name; // 都市名
double x, y; // 座標(位置)

public Point( String s, double dx, double dy ){ // コンストラクタ
    name = new String( s );
    x = dx;
    y = dy;
}
}