使用for循环计算1-100的和,除了以3结尾的那些数
package java作业; public class Java1 { /** * @param args */ public static void main(String[] args) { // TODO Auto-generated method stub int sum = 0; for (int i = 1; i <= 100; i++) { if (i % 10 != 3) { sum += i; } } System.out.println("sum=" + sum); } }
2.使用二重循环输出以下图形
*
***
*****
*******
***
*****
*******
*****
****
***
**
*
for (int i = 1; i <= 4; i++) { for (int j = 1; j <= 4 - i; j++) { System.out.print(" "); } for (int k = 1; k <= 2 * i - 1; k++) { System.out.print("*"); } System.out.println(); } System.out.println("======================="); for (int i = 1; i <= 5; i++) { for (int j = 5; j >= i; j--) { System.out.print("*"); } System.out.println(); } } }
3.循环输入学生姓名,直到输入‘Q’程序结束
package java作业; import java.util.Scanner; public class Java1 { /** * @param args */ public static void main(String[] args) { // TODO Auto-generated method stub Scanner input = new Scanner(System.in); System.out.println("输入学生姓名"); for (;;) { String name = input.next(); if (name.equals("Q")) break; } System.out.println("end"); }
4.输入5个学生成绩,求和,当输入不合法的时候,提示输入错误重新输入。
package java作业; import java.util.Scanner; public class Java1 { /** * @param args */ public static void main(String[] args) { // TODO Auto-generated method stub Scanner input = new Scanner(System.in); System.out.println("输入五个人的成绩:"); int sum = 0; for (int i = 0;;) { int grade = input.nextInt(); if (grade >= 0 && grade <= 100) { sum += grade; i++; } else { System.out.println("输入错误重新输入:"); grade = input.nextInt(); if (grade >= 0 && grade <= 100) { sum += grade; i++; } } if (i == 5) { break; } } System.out.println("sum=" + sum); } }
5.计算 1+1/(1+2) + 1/(1+2+3) +1/(1+2+3+4)+…………+1/(1+2+....+10)
package java作业; import java.util.Scanner; public class Java1 { /** * @param args */ public static void main(String[] args) { // TODO Auto-generated method stub double sum = 0; double a = 0; for (int i = 1; i <= 10; i++) { a += i; sum += 1 / a; } System.out.println("sum=" + sum); } }