Question 245042 in Html Question posted in
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Html – simple recurse code not work. what is wrong?

may beginner problem?

i implement simple recurse code.
but, it does not work.
what is wrong?

or more simple way to do?

first block is tried recurse code,
second block is sample non-recurse code. both results are should be same.

I must use recursive code.

const total = 2;

// vvvvvvvv wrong code start
let accum = 0;
let obj = [];

const loop = (total, accum, obj) => {
  for (let i = 0; i < total; i++) {
    
    obj.push(i);
    
    if (total > accum) {      
      accum++;
      loop(total, accum, obj);
    } else {
      console.log(obj);
    }
          
    obj.pop();
  }
}

loop(total, accum, obj);
// ^^^^^^^^ wrong code end

console.log('-----------------------------');

// vvvvvvvv expect result
for (let i = 0; i < total; i++) {
    for (let j = 0; j < total; j++) { 
        console.log([i, j]);
    }
}
Tags:

2

Answers


  1. 0

    You are console logging the obj but also popping from it. You need to wait until it has the length you want

    This works better

    const total = 2;
let obj = [];

const loop = (total, obj) => {
  if (obj.length === total) {
    console.log(obj.slice()); // make sure it logs a copy of the object
    return;
  }
  for (let i = 0; i < total; i++) {
    obj.push(i);
    loop(total, obj);
    obj.pop();
  }
};
loop(total, obj);
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  2. 0

    Delegate the inner loop to the same function and pass the current loop state as an arguments:

    const loop = (to, arr = [], from = 0, level = 0) => {
  
  for (let i = from; i < to; i++) {
    arr.push([i, level]);
    if(level + 1 === to) return false;
    if(!loop(to, arr, i, level + 1)){
      break;
    }
  }
  return arr;
}

//console.log(loop(2));
console.log(loop(3));
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