Java基础语法1

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SDUT Java基础语法练习1

A   C语言实验——判断素数（循环结构）(SDUT 1122)

import java.util.Scanner;

public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int n;
		n = sc.nextInt();
		if (n == 1)
			System.out.println("This is not a prime.");
		else {
			int flag = 1;
			for (int i = 2; i < n; i++) {
				if (n % i == 0) {
					flag = 0;
					break;
				}
			}
			if (flag == 1)
				System.out.println("This is a prime.");
			else
				System.out.println("This is not a prime.");
		}

	}
}

B      C语言实验——求阶乘（循环结构）（SDUT 1123）

import java.util.Scanner;

public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int n, sum = 1;
		n = sc.nextInt();
		for (int i = 1; i <= n; i++)
			sum *= i;
		System.out.println(sum);
	}
}

C        求绝对值最大值（SDUT 1147）

import java.util.Scanner;

public class Main {

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int n, x;
		int ans = 0, max1, max2 = 0;
		n = sc.nextInt();
		for (int i = 0; i < n; i++) {
			x = sc.nextInt();
			if (x <= 0)
				max1 = -x;
			else
				max1 = x;
			if (max2 < max1) {
				max2 = max1;
				ans = x;
			}
		}
		System.out.println(ans);
	}
}

D C语言实验——圆周率(SDUT 1193)

import java.util.Scanner;

public class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int n;
		double ans = 0, x, y;
		n = sc.nextInt();
		for (int i = 1; i <= n; i++) {
			x = (double) 1 / (4 * i - 3.0);
			y = (double) 1 / (4 * i - 1.0);
			ans += x - y;
		}
		ans *= 4.0;
		System.out.printf("%.5f
", ans);
	}
}

E       简单计算(SDUT 2250)

import java.util.Scanner;

public class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int n, x, min, max, ave;
		min = 0x3f3f3f3f;
		max = ave = 0;
		n = sc.nextInt();
		for (int i = 0; i < n; i++) {
			x = sc.nextInt();
			if (x > max) {
				max = x;
			}
			if (x < min) {
				min = x;
			}
			ave += x;
		}
		ave /= n;
		System.out.println(max + " " + min + " " + ave);
	}
}

F             平方数（SDUT 3439）

import java.util.Scanner;

public class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int t, n, m, a, b;
		t = sc.nextInt();
		for (int cas = 0; cas < t; cas++) {
			a = sc.nextInt();               // n和m 的大小不确定
			b = sc.nextInt();
			n = Math.min(a, b);
			m = Math.max(a, b);
			int sum = 0;
			for (int i = n; i <= m; i++) {
				double x = Math.sqrt((double) i);
				int xx = (int) x;
				if (xx * xx == i) {
					sum += i;
				}
			}
			System.out.println(sum);
		}
	}
}

G    C语言实验——for循环打印图形（循环结构）（SDUT 1121）

import java.util.Scanner;   // for循环也很简单，和c++没什么区别。这里就是凑个完整QWQ。

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

		System.out
				.println("   *
" + "  ***
" + " *****
" + "*******
" + " *****
" + "  ***
" + "   *");
	}
}

H      C/C++练习7---求某个范围内的所有素数

import java.util.Scanner;

public class Main {
	public static void main(String[] args) {
		
		Scanner sc = new Scanner(System.in);
		int n,num = 0;
		n = sc.nextInt();
		for(int i = 0; i < n; i ++)
		{
			if(prime(i) == 1) {
				num ++;
				if(num % 10 == 0) System.out.printf("%d 
",i);
				else System.out.printf("%d ", i);
			}
		}
	}
	public static int prime(int n) {
		if(n == 1 || n == 0) return 0;
		for(int i = 2; i <= (int)Math.sqrt((double)n); i ++){
			if(n % i == 0) return 0;
		}
		return 1;
	}
}