Writing a "Bean Counter" for Eloquent JavaScript Task - Stack Overflow

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In this task from Eloquent JavaScript, you are asked to write two functions. One to count the number of ""'s in a string input. The next function must take two inputs; one string to search and one string to identify the target character to search for.

I have errors in both. In the first function, my count is always returned as 1. In the second one, it simply returns undefined.

Can someone help me find my mistake?

function countBs(str) {
    var count = 0;
    for (var i = 0; i < str.length; i++) {
        if (str.charAt(i) === "B") {
            count++;
        }
        return (count);
    }
}

console.log(countBs("BBBBBBBBC"));

function countChar(str, char) {
    var count = 0;
    for (var i = 0; i < str.length; i++) {
        if (str.charAt(i) === "char") {
            count++;
            return (count);
        }
    }
}

console.log(countChar("kakkerlak", "k"));

In this task from Eloquent JavaScript, you are asked to write two functions. One to count the number of ""'s in a string input. The next function must take two inputs; one string to search and one string to identify the target character to search for.

I have errors in both. In the first function, my count is always returned as 1. In the second one, it simply returns undefined.

Can someone help me find my mistake?

function countBs(str) {
    var count = 0;
    for (var i = 0; i < str.length; i++) {
        if (str.charAt(i) === "B") {
            count++;
        }
        return (count);
    }
}

console.log(countBs("BBBBBBBBC"));

function countChar(str, char) {
    var count = 0;
    for (var i = 0; i < str.length; i++) {
        if (str.charAt(i) === "char") {
            count++;
            return (count);
        }
    }
}

console.log(countChar("kakkerlak", "k"));

• javascript

Share Improve this question Follow edited Apr 27, 2020 at 13:13 Leomord 28122 silver badges1313 bronze badges asked May 14, 2015 at 14:56 Austin HansenAustin Hansen 37411 gold badge66 silver badges1818 bronze badges 6

• I am trying to learn to code so I did the CodeCademy courses and some other online courses. One suggested resource was the Eloquent JavaScript book so I am working through that now. – Austin Hansen Commented May 14, 2015 at 15:01
• @Utkanos why is the fact that it is study (or homework) relevant? – Davin Tryon Commented May 14, 2015 at 15:03
• This line perhaps: str.charAt(i) === "char"? This line is saying that str.charAt(i) should be equal to the string value "char". You might want the parameter char. – Davin Tryon Commented May 14, 2015 at 15:05
• 1 @DavinTryon I wondered the same. I was rebuked for asking on CodeReview and they said this was indeed the place for this sort of question. If its not, then apologies. I am just passionately trying to learn a new skill independently and thought this was the purpose of this resource. – Austin Hansen Commented May 14, 2015 at 15:05
• @DavinTryon what is wrong with that line? On jsFiddle it idicates some sort of error on the "function countChar(str, char) {" line. – Austin Hansen Commented May 14, 2015 at 15:07

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7 Answers 7

Sorted by: Reset to default 5

The problem is you are returning the count within the for loop, so it returns after it searches the first character. In the second function you are also using the string "char" instead of the variable char for paring.

If you want to do it your way, here's the correct code:

function countBs(str) {
    var count = 0;
    for (var i = 0; i < str.length; i++) {
        if (str.charAt(i) === "B") {
            count++;

        }
    }
        return (count); // return outside of for loop
}



console.log(countBs("BBBBBBBBC"));


function countChar(str, char) {
    var count = 0;
    for (var i = 0; i < str.length; i++) {
        if (str.charAt(i) === char) { // use the variable char instead of  the string "char"
            count++;
        }
    }
            return (count); // return outside of the for loop
}
console.log(countChar("kakkerlak", "k"));

Here's another way to do what you want. (using regular expressions)

function countBs(str) {
    var length1 = str.length;
    var length2 = str.replace(/B/g,"").length;
    return length1 - length2;
}



console.log(countBs("BBBBBBBBC"));


function countChar(str, char) {
    var length1 = str.length;
    var regexp =  new RegExp(char, "g");
    var length2 = str.replace(regexp,"").length;
    
    return length1 - length2;
}
console.log(countChar("kakkerlak", "k"));

You've got two small errors that require the following changes:

• don't quote your char variable in the if statement
• return after the loop is plete, not after the first match

Full code for countChar():

function countChar(str, char) {
    var count = 0;
    for (var i = 0; i < str.length; i++) {
        if (str.charAt(i) === char) {
            count++;
        }
    }
    return (count);
}

//test
alert(countChar("kakkerlak", "k"));

My answer

function countBs(Str) 
{
  let char = "B" ;
  return  String(Str).split(char).length - 1; 

 } 
function countChar(Str, char) 
{
  return  String(Str).split(char).length - 1; 

 } 

function  countBs(stringVal,charVal){
    var count = 0;
    for(var i=0 ; i<stringVal.length ; i++)
    {
        if(stringVal.charCodeAt(i) === charVal.charCodeAt(0))
            count++;
    }

  return count;
}

//console.log(countBs("abcDBAB"));

function countChar(stringVal, charTobeCount){
  var newCount = countBs(stringVal, charTobeCount);
  return newCount;
}

console.log(countChar("abcDBAB", 'B'));

Bam... Short, sweet and clean.

function countChar(string, character){
    var count = 0;
    for(var x = 0; x < string.length; x++){
        if(string[x] == character) count++;
    }
    return count;
}

In the first version, your return statement is inside the inner for loop. Simply move it outside:

function countBs(str){
    let count = 0;
    for (var i = 0; i < str.length; i++){
        if (str[i] == "B") {count++;}
    }
return count;
}

Then you can easily add a second parameter by updating the code as follows:

function countChar(str, character){
    let count = 0;
    for (var i = 0; i < str.length; i++){
        if (str[i] == character) {count++;}
    }
return count;
}

At first, write the countBs function. Let's create it

function countBs(str) {
    let count = 0;
    for(let i = 0; i < str.length; i++) {
        if (str[i] === "B") {
            count++;
        }
    }

    return count;
}
console.log(countBs("BeBeBBbhBcBBBBbbbb"));

Output

9

Now using the countChar function

let countBs = function(str) {
    return countChar(str, "e");
}

function countChar(str, char) {
    let count = 0;
    for(let i = 0; i < str.length; i++) {
        if (str[i] === char) {
            count++;
        }
    }
    return count;
}
console.log(countBs("BeBeBBbhBcBeBBBbbbbebe"));

Output

5

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