Java Loop Statements, String Handling
i) Java Loop Statements
ii) String Handling in Java
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Java Conditional Statements
6) Decide among several alternates (using switch statement)
Syntax:
switch (expression){
case value:
Statements
————-
———–
———-
break;
case value:
Statements
————-
———–
———-
break;
case value:
Statements
————-
———–
———-
break;
default:
Statements
———–
———–
———–
}
Example:
public static void main(String[] args) {
char grade =’X’;
switch (grade){
case ‘A’:
System.out.println(“Excellent”);
break;
case ‘B’:
System.out.println(“Good”);
break;
case ‘C’:
System.out.println(“Better”);
break;
default:
System.out.println(“Invalid Grade”);
}
i) Java Loop Statements
Four Loop Structures in Java
1) for loop
2) while loop
3) do while loop
4) Enhanced for loop
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1) for loop
Description:
It repeats a block of statements for a specified number of times.
Syntax:
for (dataType variableName = startValue; endValue; increment/decrement){
Statements
—————
———–
}
Example 1: Print 1 to 10 Numbers
for (int i=1; i <= 10; i++){
System.out.println(i);
}
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Example 2: Print 10 to 1 Numbers
for (int i=10; i >= 1; i–){
System.out.println(i);
}
Example 3: Print 1 to 10 Numbers except 4th Number
for (int i=1; i <= 10; i++){
if (i!=4){
System.out.println(i);
}
}
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Example 4: Print 1 to 10 Numbers except 4th and 7th Numbers
for (int i=1; i <= 10; i++){
if ((i!=4) && (i!=7)){
System.out.println(i);
}
}
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2) while loop
Description
It repeats a block of statements while condition is true.
Syntax:
Initialization
while (condition){
Statements
————–
————–
increment/decrement
}
Example:
int i =1;
while (i<=10){
System.out.println(i);
i++;
}
——————
int i =10;
while (i>=1){
System.out.println(i);
i–;
}
—————————
int i =1;
while (i<=10){
if (i != 6){
System.out.println(i);
}
i++;
}
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3) do while loop
Description:
It repeats a block of statements while condition is true.
It executes a block of statements at least once irrespective of the condition.
Syntax:
Initialization;
do
{
Statements
———–
———-
increment/decrement;
} while (condition);
Example:
int i=1;
do
{
System.out.println(i);
i++;
} while (i<=10);
—————————-
int i=20;
do
{
System.out.println(i);
i++;
} while (i<=10);
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4) Enhance for loop
Description:
It executes all elements in an Array
Syntax:
Array Declaration;
for (declaration: Array){
Statements
————-
}
Example:
String [] languages = {“C”, “COBOL”, “Java”, “VBScript”};
for (String lang: languages){
System.out.println(lang);
}
Example 2:
public static void main(String[] args) {
int a=10, b=20;
int [] mathOperations = new int [3];
mathOperations[0] = a+b;
mathOperations[1] = a-b;
mathOperations[2] = a*b;
for (int operation: mathOperations){
System.out.println(operation);
}
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we can use,
a) Only Condition blocks
Example:
if (a > b){
System.out.println(“A is a Big Number”);
}
else
{
System.out.println(“B is a Big Number”);
}
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Or
b) Only Loop Blocks
for (int i = 1; i<=5; i++){
System.out.println(i);
}
Or
c) Condition/s with in a Loop block
for (int i = 1; i<=5; i++){
if (i != 3){
System.out.println(i);
}
}
Or
d) Loop/s with in a Condition
in a Java program.
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Assignment:
Loops with in a Condition
Write an Example: Insert a loop statement in If Condition
ii) String Handling in Java
What is String?
String is a sequence of characters written in double quotes.
String may have Alphabets, Numbers and Special Characters.
Example:
“India”
“123”
“India123”
“India*”
“India123*&”
“&*^%”
“Selenium Testing”
“Test Automation using Selenium and Java”
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Data Types in Computer Programming
Numbers (Integer ,Float and Double data types)
Integer (ex: 100)
byte, short, int, long
Floating point / Decimal values (Ex: 1.234)
float, double
Characters (Ex: ‘A’ or ‘a’ or ‘1’ or ‘*’)
char data type
Boolean / Logical Values (Ex: true/false)
boolean data type
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Strings (Ex: “India”, “123”)
Using String Object
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123 -Integer
1.234 – Decimal type
A – character
true/false – Logical value
“India123*” – String
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Creating Strings
String myTool = “LoadRunner”; // String Variable
String [] myTools = {“Selenium”, “UFT”, “RFT”, “SilkTest”}; //Array of Strings
System.out.println(myTool);
for (String abc: myTools){
System.out.println(abc);
}
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Operations on Strings
1) Concatenating Strings
String str1 = “Selenium “;
String str2 =”UFT”;
System.out.println(str1 + str2);//Selenium UFT
System.out.println(str1.concat(str2));//Selenium UFT
System.out.println(“Selenium ” + “UFT”);//Selenium UFT
System.out.println(“Selenium”+ 1 + 1);//Selenium11
System.out.println(1 + 1 + “Selenium”);//2Selenium
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Ex:
String + String – Concatenation
String + Integer – Concatenation
Integer + Integer – Addition
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“Selenium”+ 1 + 1 //Selenium11
Selenium1 + 1 – Selenium11
————————-
1+1+”Selenium
2 + “Selenium” – 2Selenium
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2) String Comparison
We have two types of Comparison in Computer Programming
i) 2-way Comparison (True/False)
ii) 3-way Comparison (=, >, <)
Result Criteria:
if string1 = string2 then 0
if string1 > string2 then Positive value (Greater than 0)
if string1 < string2 then negative value (Less than 0)
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ANSI Character codes
//A to Z (65 to 90)
//a to z (97 to 122)
//0 to 9 (48 to 57)
———————–
a) String Comparison using Relational Operator (==)
Supports 2-way comparison
b) String Comparison using equals() method
Supports 2-way comparison
c) String Comparison using compareTo() Method
Supports 3-way comparison
Example:
public static void main(String[] args) {
String str1 = “SELENIUM”;
String str2 = “selenium”;
String str3=”SELENIUM”;
String str4 = “zselenium”;
//String Comparison using Relational Operator (==)
System.out.println(str1 == str2);//false
System.out.println(str1 == str3);//true
//String Comparison using equals() method
System.out.println(str1.equals(str2));//false
System.out.println(str1.equals(str3));//true
//String Comparison using compareTo() Method
System.out.println(str1.compareTo(str2)); //Negative value/Less than 0
System.out.println(str1.compareTo(str3));//0
System.out.println(str4.compareTo(str2));//Positive value / Greater than 0
}
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