Java运行程序写结果(答案)

Java练习题

四、运行程序写结果

1. 当在命令提示符后输入”java SumTest 4 5”之后，下列程序的输出结果为：

4+5=9

public class SumTest

{

public static void main(String[] args)

{

int a, b, sum;

a=Integer.parseInt(args[0]);

b=Integer.parseInt(args[1]);

sum=a+b;

System.out.println(a + "+" + b + "=" + sum);

}

}

2. 当在命令提示符后输入”java PrintStar 8”之后，下列程序的输出结果为：

********

public class PrintStar {

public static void main(String[] args) {

int n = Integer.parseInt(args[0]);

int i;

for( i=1; i<=n; i++)

System.out.print("*");

System.out.println();

}

}

3. 当在命令提示符后输入”java CalculateTest 5.5”之后，下列程序的输出结果为：

10.0

public class CalculateTest{

public static void main(String args[]){

float x,y;

x = Float.parseFloat(args[0]);

if(x<1)

y = x;

else if(1<=x&&x<10)

y = 2*x-1;

else

y = 3*x-11;

System.out.println(y);

}

}

4. 当在命令提示符后输入”java Factorial3 3”之后，下列程序的输出结果为：

结果是：6

public class Factorial3 {

public static void main(String[] args) {

int num = Integer.parseInt(args[0]);

int result = 1;

if(num<1)

System.out.println("应输入大于1的整数！");

else{

int i;

for( i=1; i<=num; i++)

result = result*i;

System.out.println("结果是："+result);

}

}

}

5. 下列程序的输出结果为：null

public class X{

public static void main(String [] args)

{

String names[]=new String[5];

for(int x=0;x

names[x]=args[x];

System.out.println(names[2]);

}

}

6. 下列程序的输出结果为: 9.5 10.0 8

public class Test{

public static void main(String[] args) {

System.out.print ( 3.5+1/2+56%10+" " );

System.out.print ( 3.5+1.0/2+56%10+" " );

int a = 4%3*7+1;

System.out.println( a );

}

}

a[0] = 1 a[1] = 2 a[2] = 3

7. 下列程序的输出结果为：a[3] = 4 a[4] =5

public class A1 {

public static void main(String args[]) {

int a[]=new int[5];

a[0]=1; a[1]=2; a[2]=3; a[3]=4; a[4]=5;

System.out.print("a["+0+"] = "+a[0]+" ");

System.out.print("a["+1+"] = "+a[1]+" ");

System.out.println("a["+2+"] = "+a[2]+" ");

System.out.print("a["+3+"] = "+a[3]+" ");

System.out.print("a["+4+"] = "+a[4]);

}

}

8. 下列程序的输出结果为：a[4]=4, a[3]=3, a[2]=2, a[1]=1,a[0]=0, public class array1D_1 {

public static void main(String args[]) {

int i;

int a[ ];

a = new int[5];

for(i=0;i<5;i++)

a[i]=i;

for(i=a.length-1;i>=0;i--)

System.out.print(“a[“ +i + ”]=” + a[i] + ”,\t”);

}

}

9. 运行结果是：Hi ! Like

public class Test1 {

String str = new String("Hi !");

char[] ch = { 'L', 'i', 'k', 'e' };

public static void main(String args[]) {

Test1 ex = new Test1();

System.out.print(ex.str + " ");

System.out.print(ex.ch);