As the title suggests, I was trying to recursively solve a JavaScript problem. An exercise for my internet programming class was to invert any string that was entered in the function, and I saw this as a good opportunity to solve this with recursion. My code:
function reverseStr(str){
str = Array.from(str);
let fliparray = new Array(str.length).fill(0);
let char = str.slice(-1);
fliparray.push(char);
str.pop();
str.join("");
return reverseStr(str);
}
writeln(reverseStr("hello"))
The biggest problem is that your function doesn't have an end (base) case. It needs to have some way to recognize when it's supposed to stop or it will recurse forever.
The second problem is that you don't really seem to be thinking recursively. You're making some modification to the string, but then you just call reverseStr() all over again on the modified string, which is just going to start the process all over again.
The following doesn't really resemble your attempt (I don't know how to salvage your attempt), but it is a simple way to implement the reverse string algorithm recursively.
function reverseStr(str) {
// string is 0 or 1 characters. nothing to reverse
if (str.length <= 1) {
return str;
}
// return the first character appended to the end of the reverse of
// the portion after the first character
return reverseStr(str.substring(1)) + str.charAt(0);
}
console.log(reverseStr("Hello Everybody!"));
fliparray, which isn't actually getting used, you havestr.join(""), which doesn't reference its result, and you're reusing variables in a confusing way. Create a new variable when you doArray.from(str)so that it doesn't look like you're calling invalid methods on a string.