How do I get this recursive function to work?-CodePudding

This code should print a string, letter by letter, using recursion, i.e., without loops (do, while etc.), using a function to call itself. But it does nothing.

let str1 = 'gggGGG';

function runString(str) {
  let n = 0;

  function loop(str, n) {
    if (n === (str.length - 1)) {
      console.log('This is the end');
    }
    else {
      console.log(str[n]);
      n  ;
      
      return loop(str, n);
    }
  }
}

console.log(runString(str1));

CodePudding user response：

You could check for the end of the string and return.

Then print the first letter and call the function again with the rest of the string.

function runString(string) {
    if (!string) return;
    console.log(string[0]);
    runString(string.slice(1));
}

runString('Miracle');

CodePudding user response：

All you need to do is just to invoke the function that you have created called loop inside runString function.

let str1 = 'gggGGG';

function runString(str) {
    let n = 0;
    function loop(str, n) {
        if (n === (str.length - 1)) {
            console.log('This is the end');
        }
        else {
            console.log(str[n]);
            n  ;
            
            return loop(str, n);
        }
    }
    return loop(str, n);
}

console.log(runString(str1));

CodePudding user response：

I used your own own code, but I removed the paramethers of the 'loop' function, so it used the paramethers of it's parent function; Then I called the function 'loop'.

function runString(str) 
{ 
  let n = 0;
  
  // Here i removed the paramethers of the loop function
  function loop() { 
      if (n===(str.length)) { 
        console.log('This is the end'); 
      } 
      else {
        console.log(str[n]);
        n  ;
        return loop();
      }
    }
  
  // Here I called the function to execute
  loop()
} 

runString("gggGGG");