Explanation of switch statements

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  1. #1
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    Explanation of switch statements

    Hello-

    I have to write a program that converts numbers into words. I know I have to use switch statements for this but I dont really understand the switch statement to begin with and how it workds and in turn I dont understand how I would use them for this program. Could someone help with an explanation? I dont want a program wirrten- just how switch statements work- and how i would use them with this program. Thanks!!

    Jenna

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    Just Lurking Dave_Sinkula's Avatar
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    It's like an if statement. Post your coding attempt at it, and advise will follow.
    7. It is easier to write an incorrect program than understand a correct one.
    40. There are two ways to write error-free programs; only the third one works.*

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    ?

    can i use if statements for this instead of switch statements? I understand if statements and I would rather use them if I can. I was told switch statements would be easier. Thanks.

    Jenna

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    Just Lurking Dave_Sinkula's Avatar
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    If it helps, post your attempt using an if...else tree, and perhaps then we can show a switch equivalent.

    Or better yet -- post your "easy" if...else version, and then your attempt at converting it to a switch equivalent.
    7. It is easier to write an incorrect program than understand a correct one.
    40. There are two ways to write error-free programs; only the third one works.*

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    Reverse Engineer maxorator's Avatar
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    Code:
    if(apple==2){
        printf("Wow, there's two apples");
    }
    else if(apple==3{
        printf("Three apples! Yay!");
    }
    else if(apple==4){
        printf("So many apples!");
    }
    else{
        printf("Apple...");
    }
    equals to:
    Code:
    switch(apple){
        case 2:
            printf("Wow, there's two apples");
            break;
        case 3:
            printf("Three apples! Yay!");
            break;
        case 4:
            printf("So many apples!");
            break;
        default:
            printf("Apple...");
            break;
    }
    "The Internet treats censorship as damage and routes around it." - John Gilmore

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    Thank you!

    Thank you for your code example. I can see the relation now! Thanks!!!

  7. #7
    Algorithm Dissector iMalc's Avatar
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    Cool

    Quote Originally Posted by ammochck21
    Hello-

    I have to write a program that converts numbers into words. I know I have to use switch statements for this but I dont really understand the switch statement to begin with and how it workds and in turn I dont understand how I would use them for this program. Could someone help with an explanation? I dont want a program wirrten- just how switch statements work- and how i would use them with this program. Thanks!!

    Jenna
    A switch statement is often not the only option. If the numbers you are using are all consecutive then you can use a simple array lookup.
    This works especially well if you use enums for your item types.
    Code:
    enum fruitType {APPLE, BANANA, CHERRY};
    const std::string fruitName[] = {"Apple", "Banana", "Cherry"};
    
    fruitType f = BANANA;
    cout << fruitName[static_cast<int>f];
    Easy as ABC.

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