709. Convert to lowercase letters

Title Description

Implementation function ToLowerCase(), This function takes a string parameter str, And convert the upper case letters in the string to lower case letters , Then return the new string .
https://leetcode-cn.com/problems/to-lower-case/

Their thinking

There are two ways to achieve ：

1. Call directly js In the string toLowerCase Method realization .
2. A-Z Of ASCII The value is 65-90.a-z The value is 97-122. In lowercase ASCII Value is its corresponding capital letter ASCII Value plus 32.

Code implementation

/** * @param {string} str * @return {string} */
 //1.toLowerCase 88 ms 33.8 MB
var toLowerCase = function(str) {
    
  return str.toLowerCase();
};


//A~Z Of ASCII The value is 65~90.
//a~z Of ASCII The value is 97~122.
// In lowercase ASCII Value is its corresponding capital letter ASCII Value plus 32. 64 ms 33.7 MB
var toLowerCase = function(str) {
    
  let res='';
  for(let i=0;i<str.length;i++){
    
    let code=str.charCodeAt(i);
    if(code>=65&&code<=90){
    
      res+=String.fromCharCode(code+32);
    }else{
    
      res+=str[i];
    }
  }
  return res;
  str.toLowerCase
};