If 语句中的检查问题

Question

Hello guys I have a problem with an If statement. I have 2 checking inside of it and I don't know why one of them is not working. Sorry if my code is not the best but a beginner and I'm trying to improve thank you very much.

this is the one else if (command == 'hit' && p3 > 0)

if (command == `bj`){

        var p1 = 0;
        var p2 = 0;
        
        const Boolean = true;

        p1 = Math.floor((Math.random() * 11) + 1);
        p2 = Math.floor((Math.random() * 11) + 1);
        message.channel.send(`First card: ` + p1);
        message.channel.send(`Second card: ` + p2);
        var p3 = p1 + p2;
        message.channel.send(`total : ` + p3);

    } else if (command == `hit` && p3 > 0){

        message.channel.send(`checking worked !`);

    } else {
            message.channel.send(`Not Working!`);
    }

Answer 1

You are correct about the problem: the code inside } else if (command == 'hit' && p3 > 0){ will never run.

This is because of the way if/else statements work in Javascript. The interpreter looks at the condition, and if the condition is true, the interpreter executes the code inside that block. If the condition is false, the interpreter skips that code block completely and moves to the next condition.

So, in your code, when command === 'bj' :

if (command == `bj`){ // command is 'bj', run this code block, skip the other cases

        var p1 = 0;
        var p2 = 0;
        
        const Boolean = true;

        p1 = Math.floor((Math.random() * 11) + 1);
        p2 = Math.floor((Math.random() * 11) + 1);
        message.channel.send(`First card: ` + p1);
        message.channel.send(`Second card: ` + p2);
        var p3 = p1 + p2;
        message.channel.send(`total : ` + p3);

    } else if (command == `hit` && p3 > 0){ // this block doesn't run, it's skipped

        message.channel.send(`checking worked !`);

    } else { // this block doesn't run, it's skipped
            message.channel.send(`Not Working!`);
    }

Now, in your code, when command === 'hit' :

if (command == `bj`){ // command is 'hit', skip this code block completely

        var p1 = 0;
        var p2 = 0;
        
        const Boolean = true;

        p1 = Math.floor((Math.random() * 11) + 1);
        p2 = Math.floor((Math.random() * 11) + 1);
        message.channel.send(`First card: ` + p1);
        message.channel.send(`Second card: ` + p2);
        var p3 = p1 + p2;
        message.channel.send(`total : ` + p3);

    } else if (command == `hit` && p3 > 0){ // command is 'hit', but p3 has no value -- the block in which it's given a value is never run!

        message.channel.send(`checking worked !`);

    } else { // this block doesn't run, it's skipped
            message.channel.send(`Not Working!`);
    }

To get the results you want, you need to re-think how to accomplish this.

Answer 2

Since you declared p2 in a separate statement, it will not be readable in the other if statement. If you want to update a variable, use let eg let p2 = Math.floor((Math.random() * 11) + 1);

If you would benefit from a guide on Javascript, I would suggest reading this one https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide .

Also, instead of using an else if off the main statement, why not use 2 if statements? It achieves the effect you want. Here is an example:

if (command == `bj`){
        let commandState = 1 //state variable to allow the hit command to know whether the bj command has been called (since hit is dependent on bj)
        var p1 = 0;
        var p2 = 0;
        
        const Boolean = true;

        p1 = Math.floor((Math.random() * 11) + 1);
        p2 = Math.floor((Math.random() * 11) + 1);
        message.channel.send(`First card: ` + p1);
        message.channel.send(`Second card: ` + p2);
        let p3 = p1 + p2;
        message.channel.send(`total : ` + p3);
} 


if (command == 'hit'){
       if (!commandState) return; //If the command state is not 1, or true, leave the statement
       if (p3 > 0) {
           message.channel.send("Success")
       } else {
           message.channel.send("Failure")
       }
}

You also seem to be using backticks as string operators. Backticks are only used when you need to use embedded information in your string eg (`${message.author.id}`) Using normal quotation marks will work well in all other cases - pick which you like ("example 1", 'example 2')