1、输入与输出
import java.util.*;
class InputTest{
public static void main(String args[]){
Scanner reader=new Scanner(System.in);
int n;
while(!reader.hasNextInt()){
reader.nextLine();
System.out.println("输入格式错误,请重新输入:");
}
n=reader.nextInt();
System.out.println("n="+n);
}
}
2、除法运算
import java.util.*;
class Division{
public static void main(String args[]){
Scanner reader=new Scanner(System.in);
int a,b=0;
double q;
System.out.println("请输入被除数:");
while(!reader.hasNextInt()){
reader.nextLine();
System.out.println("输入格式错误,请重新输入:");
}
a=reader.nextInt();
System.out.println("请输入除数:");
while(!reader.hasNextInt()){
reader.nextLine();
System.out.println("输入格式错误,请重新输入:");
}
b=reader.nextInt();
if(0==b){
System.out.println("输入格式错误,请重新输入:");
b=reader.nextInt();
}
q=(double)a/b;
System.out.printf("除数算式及运算结果:\n%10d/%d=%10.2f",a,b,q);
}
}
3、数组
class ArrayTest{
public static void main(String args[]){
int []b=new int[10];
int []a={5,6,7,8};
System.out.println(b);
System.out.println();
for(int i=0;i<=3;i++)
System.out.println(a[i]);
System.out.println();
b=a;
System.out.println(b.length);
}
}
4、课程表
import java.util.*;
class Schedule{
public static void main(String args[]){
boolean[][]table=new boolean[7][5];
int i,j;
while(true){
System.out.println("请输入星期:(1-7分别代表周一至周日)");
i=input();
System.out.println("请输入节次:(1-5分别代表1、2节至9、10节各个时间段)");
j=input();
if(i>0&&i<8&&j>0&&j<6){
table[i-1][j-1]=true;
}else
break;
}
System.out.println();
System.out.println(" 周一 周二 周三 周四 周五 周六 周日 ");
System.out.println();
for(int a=0;a<10;a++){
System.out.printf("%d",a+1);
for(int b=0;b<7;b++){
System.out.printf(" ");
if(table[b][a/2]==true){
System.out.printf("Java");
}else
System.out.printf(" ");
}
System.out.println("");
}
}
private static int input(){
Scanner reader=new Scanner(System.in);
while(!reader.hasNextInt()){
reader.nextLine();
System.out.println("输入格式错误,请重新输入:");
}
return reader.nextInt();
}
}
5、运算符
class OperatorTest{
public static void main(String args[]){
int a=3,b=4,c=5,d=6,m=7,n=8;
int x=64,arr[]=new int[8];
long y=-0x1000000000L,z=4;
boolean flag;
flag = a>3 && b-->4;
flag = ++c>5 || ++d>6;
flag = m==7 | ++n==8;
x>>=33;
y>>=33;
z>>=65;
System.out.printf("a=%d,b=%d;c=%d,d=%d,m=%d,n=%d\n",a,b,c,d,m,n);
System.out.printf("x=%d,y=%d,z=%d,x^z=%d\n",x,y,z,x^z);
System.out.println(arr instanceof int[]);
}
}
6、流程控制
import java.util.*;
public class ControlTest{
public static void main(String args[]){
System.out.println("请输入一个整数:");
int n=input();
for (int i=0;i<n;i++){
if (i%2==0)
continue;
if (i%n==6)
break;
System.out.println("i="+i);
}
}
private static int input(){
Scanner reader=new Scanner(System.in);
while (!reader.hasNextInt()){
reader.nextLine();
System.out.println("输入格式错误,请重新输入:");
}
return reader.nextInt();
}
}