Jump statements

Jump statements are used to transfer control from one point to another point in the program using some specified code while executing the program. In simple terms, while using jump statement control will jump from one point to another point. There are five keywords in the Jump Statements. we'll see all those with its definition below.

1. goto - This statement is used to transfer control to the labeled statement in the program. The label is the valid identifier.
2. break - The break statement is used to terminate the loop or switch statement depending on where it present.
3. return (will study about this in detail in upcoming articles) - This statement terminates the execution of the method and returns the control to the calling method. It returns an optional value.
4. continue - This statement is used to skip over certain execution part of the loop on a certain condition
5. throw - This is used to create an object of any valid exception class with the help of new keyword manually. The valid exception must be derived from the Exception class.

NOTE
Not all jump statements are widely used. The widely used keywords in jump statements are break, return and goto. continue and throw will be rarely used.

CODE

EG 1 . Login application using Goto statement

static void Main(string[] args) {
    Start:
    //Getting Username
    Console.Write("Enter Username : ");
    string username = Console.ReadLine();
    //Getting Password
    Console.Write("Enter Password : ");
    string password = Console.ReadLine();

    //Here we used Logical AND(&&), so both LHS and RHS condition need to True in order to make entire condition True
    switch (username == "info@coderscapsule.com" && password =="123456789") {
        case true:
        Console.WriteLine("You have unlocked your Phone!!!");
        break;
        case false:
        Console.WriteLine("Invalid Username/Password");
        break;
    }
    goto Start;
}

CODE EXPLANATION
In the above code, we used label called Start. The code will be executed from top to bottom and when system reaches goto Start, system will jump from that line to Start label and again excute everything from top to bottom, again it will jump and execute everything. Here we created a infinite chance Login application where system will keep on asking user to enter Username and Password.


EG 2 . Login application using break statement

static void Main(string[] args) {
    //Getting Username
    Console.Write("Enter Username : ");
    string username = Console.ReadLine();
    //Getting Password
    Console.Write("Enter Password : ");
    string password = Console.ReadLine();

    //Here we used Logical AND(&&), so both LHS and RHS condition need to True in order to make entire condition True
    switch (username == "info@coderscapsule.com" && password =="123456789") {
        case true:
        Console.WriteLine("You have unlocked your Phone!!!");
        break;
        case false:
        Console.WriteLine("Invalid Username/Password");
        break;
    }
}

CODE EXPLANATION
In the above code, we used break inside switch statement. The function of that Break keyword is to terminate switch statement. Once that break keyword executed, system will jump outside switch statement. Just because it is jumping outside switch statement it is coming under jump Statement. Same rule applicable for Loop also. Break keyword can be used inside Loop, if that break keyword executed that will terminate respective loop.


EG 3 . Creating For loop using continue keyword

static void Main(string[] args) {
    for (int i = 1; i <= 5; i++) {
    // if the value of i becomes 3, system will skip 3 and send the transfer to the for loop and continue with 4
    if (i == 3) {
        continue;
    }
    Console.WriteLine(i);
}

OUTPUT
1
2
4
5

CODE EXPLANATION
In the above code, we used continue inside for loop. The function of that continue keyword is to transfer execution part again to the for loop without executing below code. This statement skips the current iteration and passes program control to the next iteration of the enclosing loop in which it appears.


EG 4 . Creating For loop and throwing exception in the middle

static void Main(string[] args) {
    for (int i = 1; i <= 5; i++) {
    // if the value of i becomes 3, system will throw a Exception message stating "This is my Exception".
    if (i == 3) {
        throw new NullReferenceException("This is my Exception"); ;
    }
    Console.WriteLine(i);
}

OUTPUT
1
2
*Exception Thrown*

CODE EXPLANATION
In the above code, we used throw inside for loop. The function of that throw keyword is to create an object of any valid exception class with the help of new keyword manually. This statement throws an exception which indicate that an error has occurred during the program execution. This statement is used with a combination of try-catch statement. Try executing above code we can clearly understand what exception is.


Exercises
1. Create login application where if user enters wrong username or password system should give 3 attempts. if user enters correct username and password system should terminate that loop.
2. Write a for loop that print 1 to 100, skip only the even numbers using continue keyword.
3. Create login application where if user enters wrong username or password system should give infinte attempts using continue keyword.
4. Get Multiplication table and limit value from user and print that multiplication table from 1 to entered limit. Create this a infinte loop using goto.


(Click Here, For more exercises)