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/switch-statement" style="z-index:9999;width:500px;">



what is switch statement?

switch statement perform multi way decision statement. the switch statement test the value of given variable or expression against a list of case values and when a match is found. a block of statement associated with that case is executed.

When you want to solve multiple option type problems, for example: Menu like program, where one value is associated with each option and you need to choose only one at a time, then, switch statement is used.

switch(expression)
{
case value-1:
block-1;
break;
case value-2:
block-2;
break;
case value-3:
block-3;
break;
case value-4:
block-4;
break;
default:
default-block;
break;
}

Rules for switch statement in C language :-

  • The switch expression must be of integer or character type.
  • The case value must be integer or character constant.
  • The case value can be used only inside the switch statement.
  • The break statement in switch case is not must. It is optional. If there is no break statement found in switch case, all the cases will be executed after matching the case value. It is known as fall through state of C switch statement.
  • The case label values must be unique.
  • The case label must end with a colon(:)

    • Points to Remember :-

  • We don't use those expressions to evaluate switch case, which may return floating point values or strings or characters.
  • break statements are used to exit the switch block. It isn't necessary to use break after each block, but if you do not use it, then all the consecutive blocks of code will get executed after the matching block.
  • Valid expressions for switch :- switch(1+2+23) switch(1*2+3%4)
  • Invalid switch expressions :- switch(ab+cd) switch(a+b+c)

    • int i = 1;
    switch(i)
    {
    case 1:
    printf("A"); // No break
    case 2
    printf("B"); // No break
    case 3:
    printf("C");
    break;
    }


    Output :-

    A B C

    The output was supposed to be only A because only the first case matches, but as there is no break statement after that block, the next blocks are executed too, until it a break statement in encountered or the execution reaches the end of the switch block.

    default case is executed when none of the mentioned case matches the switch expression. The default case can be placed anywhere in the switch case. Even if we don't include the default case, switch statement works.

    Nesting of switch statements are allowed, which means you can have switch statements inside another switch block. However, nested switch statements should be avoided as it makes the program more complex and less readable.

    void main( )
    {
    int a, b, c, choice;
    while(choice != 3)
    { /* Printing the available options */
    printf("\n 1. Press 1 for addition");
    printf("\n 2. Press 2 for subtraction");
    printf("\n Enter your choice");
    /* Taking users input */
    scanf("%d", &choice);
    switch(choice)
    {
    case 1:
    printf("Enter 2 numbers");
    scanf("%d%d", &a, &b);
    c = a + b;
    printf("%d", c);
    break;
    case 2:
    printf("Enter 2 numbers");
    scanf("%d%d", &a, &b);
    c = a - b;
    printf("%d", c);
    break;
    default:
    printf("you have passed a wrong key");
    printf("\n press any key to continue");
    }
    }
    }

    Difference between switch and if :-

  • if statements can evaluate float conditions. switch statements cannot evaluate float conditions.
  • if statement can evaluate relational operators. switch statement cannot evaluate relational operators i.e they are not allowed in switch statement.

    • int main(){
    int number=0;
    printf("enter a number:");
    scanf("%d",&number);
    switch(number){
    case 10:
    printf("number is equals to 10");
    break;
    case 50:
    printf("number is equal to 50");
    break;
    case 100:
    printf("number is equal to 100");
    break;
    default:
    printf("number is not equal to 10, 50 or 100");
    }
    return 0;
    }

    Example :-

    #include
    int main()
    {
    int num=2;
    switch(num+2)
    {
    case 1:
    printf("Case1: Value is: %d", num);
    case 2:
    printf("Case1: Value is: %d", num);
    case 3:
    printf("Case1: Value is: %d", num);
    default:
    printf("Default: Value is: %d", num);
    }
    return 0;
    }

    output :-

    Default: value is: 2
    I gave num+2, where num value is 2 and after addition the expression resulted 4. Since there is no case defined with value 4 the default case is executed.

    Example :-

    #include
    int main()
    {
    int i=2;
    switch (i)
    {
    case 1:
    printf("Case1 ");
    case 2:
    printf("Case2 ");
    case 3:
    printf("Case3 ");
    case 4:
    printf("Case4 ");
    default:
    printf("Default ");
    }
    return 0;
    }

    output :-

    ase2 Case3 Case4 Default

    I passed a variable to switch, the value of the variable is 2 so the control jumped to the case 2, However there are no such statements in the above program which could break the flow after the execution of case 2. That’s the reason after case 2, all the subsequent cases and default statements got executed.

    You can also use characters in switch case. Example :-

    #include
    int main()
    {
    char ch='b';
    switch (ch)
    {
    case 'd':
    printf("CaseD ");
    break;
    case 'b':
    printf("CaseB");
    break;
    case 'c':
    printf("CaseC");
    break;
    case 'z':
    printf("CaseZ ");
    break;
    default:
    printf("Default ");
    }
    return 0;
    }

    output :-

    CaseB


    A PHP Error was encountered

    Severity: Warning

    Message: Undefined variable $cate

    Filename: views/tutorial.php

    Line Number: 354

    Backtrace:

    File: /home/ittubixb/public_html/application/views/tutorial.php
    Line: 354
    Function: _error_handler

    File: /home/ittubixb/public_html/application/controllers/Ittutorial.php
    Line: 135
    Function: view

    File: /home/ittubixb/public_html/index.php
    Line: 315
    Function: require_once

    /switch-statement" style="z-index:9999;width:500px;">


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