[코드업 기초100제]1037~1050

몰랐던거 정리

✔️ - 단항연산자

System.out.println(-(input));
// input은 int형 변수이고
// 출력결과는 부호가 반대로 바뀜. 3 -> -3

✔️ % 연산자는 음이 아닌 정수에 대해서만 계산 가능

✔️ 시프트연산자

✔️ Convert boolean to int = 삼항연산자

• 강제 형변환이 불가능 하므로, 삼항연산자이용

// compare() 은 boolean을 반환하는 함수.

// error
System.out.println((int)q.compare(left,right)); 
// error
System.out.printf("%d",q.compare(left,right)); 
// correct
int result = q.compare(left,right) ? 1 : 0;
System.out.println(reslut);

✔️ 144번 error : 형변환

// int형 입력을 받고 그 값에 1을 더해 출력하는 문제인데, 
// 형변환을 해주어야 int범위의 최대값이 입력됐을 때 의도된 값이 나온다. 

long result = input+1;  // 강제형변환 못해서 error 
long result = (long)input+1; // 고친거 

---

137번

public class Q1037 {
    public static void main(String[] args) {

        Scanner sc = new Scanner(System.in);

        int input = sc.nextInt();

        sc.close();

        System.out.println((char)input);
    }

}

---

138번

public class Q1038 {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);

        int first = sc.nextInt();
        int second = sc.nextInt();

        sc.close();

        if ((first+second) >= 2147483647 || (first+second) <= -2147483648) {
            System.out.println((long) first + second);
        } else {
            System.out.println(first + second);
        }
    }
}

---

140번

public class Q1040 {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);

        int input = sc.nextInt();

        sc.close();

        System.out.println(-(input));
    }
}

---

141번

public class Q1041 {
    public static void main(String[] args) throws IOException {
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
        char input = (char) br.read();

        br.close();

        System.out.println((char) (input + 1));
    }
}

---

142번

public class Q1042 {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);

        int a = sc.nextInt();
        int b = sc.nextInt();

        sc.close();

        System.out.println((int)(a / b));

    }
}

---

143번

public class Q1043 {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);

        int a = sc.nextInt();
        int b = sc.nextInt();

        sc.close();

        System.out.println(a % b);

    }
}

---

144번

public class Q1044 {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);

        int input = sc.nextInt();
        sc.close();

        //  long result = input+1;
        long result = (long)input+1;

        System.out.println(result);

    }
}

---

145번

public class Q1045 {

    public void plus(int second, int first) {
        System.out.println(first + second);
    }

    public void minus(int first, int second) {
        System.out.println(first - second);
    }

    public void multiple(int first, int second) {
        System.out.println(first * second);
    }

    public void body (int first, int second) {
        System.out.println((int)first / second);
    }

    public void tail (int first, int second) {
        System.out.println(first % second);
    }

    public void division (int first, int second) {
        System.out.printf("%.2f\n" , (float)first / second);
    }

    public static void main(String[] args) {

        Scanner sc = new Scanner(System.in);
        int first = sc.nextInt();
        int second = sc.nextInt();
        sc.close();

        Q1045 q = new Q1045();

        q.plus(first,second);
        q.minus(first,second);
        q.multiple(first,second);
        q.body(first,second);
        q.tail(first,second);
        q.division(first,second);

    }
}

---

146번

public class Q1046 {

    public int plus(int a,int b,int c) {
        return a+b+c;
    }

    public float average(int a,int b, int c) {
        return (float) (a+b+c) / 3;
    }

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int first = sc.nextInt();
        int second = sc.nextInt();
        int third = sc.nextInt();
        sc.close();

        Q1046 q = new Q1046();

        System.out.println(q.plus(first,second,third));
        System.out.printf("%.1f",q.average(first,second,third));
    }
}

---

147번

public class Q1047 {

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int input = sc.nextInt();
        sc.close();

        System.out.println(input<<1);
    }
}

---

148번

public class Q1048 {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        int first = sc.nextInt();
        int second = sc.nextInt();
        sc.close();

        System.out.println(first<<second);
    }
}

---

149번

public class Q1049 {

    public boolean compare(int left, int right) {
        if (left > right) {
            return true;
        }else { return false; }
    }

    public static void main(String[] args) {

        Scanner sc = new Scanner(System.in);
        int left = sc.nextInt();
        int right = sc.nextInt();
        sc.close();

        Q1049 q = new Q1049();

        // boolean to int 하는 방법. 아래 두가지는 오류. 세번째만 사용가능
        // System.out.println((int)q.compare(left,right));
        // System.out.printf("%d",q.compare(left,right));
        int result = q.compare(left,right) ? 1:0;
        System.out.println(result);


    }

}

---

150번

public class Q1050 {

    public boolean compare(int a, int b) {
        if (a == b) {
            return true;
        } else { return false; }
    }

    public static void main(String[] args) {

        Scanner sc = new Scanner(System.in);
        int first = sc.nextInt();
        int second = sc.nextInt();
        sc.close();

        Q1050 q = new Q1050();

        int result = q.compare(first,second) ? 1:0;
        System.out.println(result);

    }

}

---