Twelve Classical Examples of Java Programming
- 2021-12-04 10:11:29
- OfStack
Directory Example 1: Character Type Variable Example 2: Data Type Conversion Example 3: Encryption and Decryption of Characters Using XOR Example 4: Difference between Short Circuit Logical OR () and Bit Operation () Example 5: Sort the values of a, b and c with if statement from small to large
Example 6: Use if statement to judge whether a given score passes Example 7: Use switch statement Example 8: Use for loop to calculate 5 + 55 + 555 +. . . The sum of the first 10 items of
Example 9: Using the while loop, calculate 1 + 1/2! + 1/3! + 1/4! + + 1/20! Example 10: Calculate the sum of the numbers of a given integer Example 11: break and continue use examples, respectively, calculate the odd sum of numbers within 10, calculate prime numbers within 50 Example 11: 1-dimensional array Example, output the element with the smallest value in the 1-dimensional integer array and its subscript Example 12: Calculate the sum of the elements in the 2-dimensional array and find the row with the largest value
Example 5: Using if statement to sort the values of a, b and c from small to large
Example 8: Calculate 5 + 55 + 555 + using the for loop. . . The sum of the first 10 items of
Example 1: Character variable
public class CharacterTest {
public static void main (String args[ ]) {
char chinaWord=' You ',japanWord=' Shiri ';
int p1=36328,p2=38358;
System.out.println(" Chinese characters ' You ' In unicode Sequential positions in a table :"+(int)chinaWord);
System.out.println(" Japanese ' Shiri ' In unicode Sequential positions in a table :"+(int)japanWord);
System.out.println("unicode Table number 20328 The character in the position is :"+(char)p1);
System.out.println("unicode Table number 12358 The character in the position is :"+(char)p2);
}
}
Example 2: Data type conversion
public classDataTypeTest {
public static void main (String args[ ]) {
int c=2200;
long d=8000;
float f;
double g=123456789.123456789;
c=(int)d;
f=(float)g; // Lead to a loss of accuracy .
System.out.print("c= "+c);
System.out.println(" d= "+d);
System.out.println("f= "+f);
System.out.println("g= "+g);
}
}
Example 3: Encrypting and Decrypting Characters Using XOR
class XORTest {
public static void main(String args[]){
char a1='10',a2=' Point ',a3=' Advance ',a4=' Attack ';
char secret='8';
a1=(char)(a1^secret);
a2=(char)(a2^secret);
a3=(char)(a3^secret);
a4=(char)(a4^secret);
System.out.println(" Ciphertext :"+a1+a2+a3+a4);
a1=(char)(a1^secret);
a2=(char)(a2^secret);
a3=(char)(a3^secret);
a4=(char)(a4^secret);
System.out.println(" Original text :"+a1+a2+a3+a4);
}
}
Example 4: The difference between short-circuit logical OR () and bit operation ()
class OrTest {
public static void main(String args[]) {
int x,y=10;
if(((x=0)==0)||((y=20)==20)) {
System.out.println(" Now y The value of is :"+y);
}
int a,b=10;
if(((a=0)==0)|((b=20)==20)) {
System.out.println(" Now b The value of is :"+b);
}
}
}
Example 5: Using if statement to sort the values of a, b and c from small to large
public class SortABC{
public static void main(String args[]){
int a=9,b=5,c=7,t;
if(a>b) {
t=a; a=b; b=t;
}
if(a>c) {
t=a; a=c; c=t;
}
if(b>c) {
t=b; b=c; c=t;
}
System.out.println("a="+a+",b="+b+",c="+c);
}
}
Example 6: Use if statement to judge whether a given grade passes or not
public class Score {
public static void main(String args[]){
int math=65 ,english=85;
if(math>=60) {
System.out.println(" Pass the math ");
}
else {
System.out.println(" Fail math ");
}
if(english>90) {
System.out.println(" English is excellent ");
}
else {
System.out.println(" English is not excellent ");
}
System.out.println(" I'm learning control statements ");
}
}
Example 7: Use of switch statement
When the main program executes, if the first command-line argument is numeric, lowercase, and uppercase, the first character will be displayed. If the input is not a number or letter, it is not a number or letter.
class Ex2_07 {
public static void main(String[] args) {
char ch = args[0].charAt(0);
switch (ch) {
case '0': case '1': case '2': case '3': case '4':
case '5': case '6': case '7': case '8': case '9':
System.out.println("The character is digit " + ch);
break;
case 'a': case 'b': case 'c': case 'd': case 'e': case 'f': case 'g':
case 'h': case 'i': case 'j': case 'k': case 'l': case 'm': case 'n':
case 'o': case 'p': case 'q': case 'r': case 's': case 't': case 'u':
case 'v': case 'w': case 'x': case 'y': case 'z':
System.out.println("The character is lowercase letter " + ch);
break;
case 'A': case 'B': case 'C': case 'D': case 'E': case 'F': case 'G':
case 'H': case 'I': case 'J': case 'K': case 'L': case 'M': case 'N':
case 'O': case 'P': case 'Q': case 'R': case 'S': case 'T': case 'U':
case 'V': case 'W': case 'X': case 'Y': case 'Z':
System.out.println("The character is uppercase letter " + ch);
break;
default:
System.out.println("The character " + ch
+ " is neither a digit nor a letter.");
}
}
}
Example 8: Calculate 5 + 55 + 555 + using the for loop. . . The sum of the first 10 items of
public class Example3_6{
public static void main(String args[]){
long sum=0,a=5,item=a,n=10,i=1;
for(i=1;i<=n;i++) {
sum=sum+item;
item=item*10+a;
}
System.out.println(sum);
}
}
Example 9: Using the while loop, calculate 1 + 1/2! + 1/3! + 1/4! + + 1/20! Value of
class Example3_7 {
public static void main(String args[]) {
double sum=0,a=1;
int i=1;
while(i<=20) {
sum=sum+a;
i=i+1;
a=a*(1.0/i);
}
System.out.println("sum="+sum);
}
}
Example 10: Calculating the sum of the numbers of a given integer
class Ex2_10 {
public static void main(String args[]) {
int x = 12345;
int y=x;
int r=0;
int sum = 0;
while(y!=0) {
r = y % 10;
sum += r;
y = y / 10;
}
System.out.println("x -> " + sum);
}
}
Example 11: break and continue are used as examples to calculate odd sums within 10 and prime numbers within 50 respectively
public classDataTypeTest {
public static void main (String args[ ]) {
int c=2200;
long d=8000;
float f;
double g=123456789.123456789;
c=(int)d;
f=(float)g; // Lead to a loss of accuracy .
System.out.print("c= "+c);
System.out.println(" d= "+d);
System.out.println("f= "+f);
System.out.println("g= "+g);
}
}
Example 11: 1-Dimensional Array for example, output the element with the smallest value in 1-Dimensional Integer Array and its subscript)
public classDataTypeTest {
public static void main (String args[ ]) {
int c=2200;
long d=8000;
float f;
double g=123456789.123456789;
c=(int)d;
f=(float)g; // Lead to a loss of accuracy .
System.out.print("c= "+c);
System.out.println(" d= "+d);
System.out.println("f= "+f);
System.out.println("g= "+g);
}
}
Example 12: Calculate the sum of the elements of each row in a 2-dimensional array and find the row with the largest value
public classDataTypeTest {
public static void main (String args[ ]) {
int c=2200;
long d=8000;
float f;
double g=123456789.123456789;
c=(int)d;
f=(float)g; // Lead to a loss of accuracy .
System.out.print("c= "+c);
System.out.println(" d= "+d);
System.out.println("f= "+f);
System.out.println("g= "+g);
}
}