07-30 数组

int[] array1=new int[10];
Scanner scanner=new Scanner(System.in);
for (int i = 0; i < array1.length; i++) {
array1[i]=scanner.nextInt();
}
for (int j = 0; j < array1.length; j++) {
System.out.println(array1[j]);
}
int[] array2={1,2,3,4,5,6,7};
for (int j = 0; j < 7; j++) {
System.out.println(array2[j]);
}

double[] scores=new double[5];
Scanner scanner=new Scanner(System.in);
double sum=0;
for (int i = 0; i < scores.length; i++) {
System.out.println("请输入数据:");
scores[i]=scanner.nextDouble();
sum=sum+scores[i];
}
System.out.println("平均分是"+sum/5);

int[] array={52,75,73,42,36,92};
for (int i = 0; i < array.length-1; i++) {
for (int j = 0; j < array.length-i-1; j++) {
int temp=0;
if(array[j]>array[j+1]){
temp=array[j];
array[j]=array[j+1];
array[j+1]=temp;
}
}
}
//Arrays.sort(array);（排序方法）
for (int i = 0; i < array.length; i++) {
System.out.println(array[i]);
}

int[] array={52,75,73,42,36,92};
int[] array1=Arrays.copyOfRange(array, 1,4);
for (int i = 0; i < array1.length; i++) {
System.out.println(array1[i]);
}

int[] array={52,75,73,42,36,92};
int[] array2=new int[10];
System.arraycopy(array, 1, array2, 1, 4);
for (int i = 0; i < array2.length; i++) {
System.out.println(array2[i]);
}

int[][] array=new int[3][];
array[0]=new int[]{1,2,3,4,5};
System.out.println(array[0][1]);

int[][] array1=new int [2][3];
array1[1]=new int[]{1,2,3,4,5};
System.out.println(array1[1][4]);

int[][] array2={{1,2,3},{4,5,6},{7,8,9}};
System.out.println(array2[1][2]);

System.out.println("请输入邮箱地址:");
Scanner scanner=new Scanner(System.in);
String email=scanner.next();

if(email.contains("@")){
int index=email.indexOf("@");
String start=email.substring(0, index);
boolean isLetterOrNum=true;
for (int i = 0; i < start.length(); i++) {
char ch=start.charAt(i);
if(!Character.isLetterOrDigit(ch)){
break;
}
}
if(isLetterOrNum==false){
System.out.println("起始不是字母或数字!");
}

if(email.contains(".")){
int index1=email.lastIndexOf(".");
String center=email.substring(index+1, index1);
boolean isNumOrLetter=true;
for (int i = 0; i < center.length(); i++) {
char ch1=center.charAt(i);
if(!Character.isDigit(ch1)){
break;
}
}
if(isNumOrLetter==false){
System.out.println("中间不是数字!");
}

}else{
System.out.println("缺少.符号!");
}

boolean end=false;
if(email.endsWith(".com")||email.endsWith(".cn")){
end=true;
System.out.println("邮箱格式正确!");
}else{
System.out.println("结尾格式格式错误!");
}

}else{
System.out.println("缺少@符号!");
}

String str="asdQWQzxc";
String s="";
for (int i = 0; i < str.length(); i++) {
char c=str.charAt(i);
boolean islower=Character.isLowerCase(c);
if(islower){
c=Character.toUpperCase(c);
}else{
c=Character.toLowerCase(c);
}
s=s+c;
}
System.out.println(s);

Random ran=new Random();
int[] array=new int[10];
for (int i = 0; i < array.length; i++) {
array[i]=ran.nextInt(90)+10;
System.out.print(array[i]+" ");
}
System.out.println();
Arrays.sort(array);
System.out.println(Arrays.toString(array));

int[][] array=new int[4][4];
Random ran=new Random();
for (int i = 0; i < array.length; i++) {
for (int j = 0; j < array.length; j++) {
array[i][j]=ran.nextInt(10);
System.out.print(array[i][j]+"\t");
}
System.out.println();
}

int temp1=1;
int temp2=1;
for (int i = 0; i < array.length; i++) {
temp1=temp1*array[i][i];  //array[i][i]可以直接取值
temp2=temp2*array[i][4-i-1];
}
System.out.println("主对角线乘机为:"+temp1);
System.out.println("副对角线乘机为:"+temp2);