C++ Program to Convert String UPPERCASE to lowercase

Question : Write a C++ Program to Convert String UPPERCASE to lowercase?

Explain: C++ Language Question about conversion String UPPERCASE to lowercase with input from user.

Formula: 
65 to 90 ASCII code for Upper characters 
97 to 122 ASCII code for Upper characters 
so for conversion upper case to lower case +32  
for example A ASCII code is 65 for convert lower case add 32 now 141 is equal to lowercase a

Solution:

 /************************************************************ 
     C++ Program for Convert String UPPERCASE to lowercase
 *************************************************************
***************** By www.cpplanguage.com *********************/

#include<iostream>
#include<string>
using namespace std;
int main()
{
  int c,length;
  char string[20];
  cout<<"Enter You String Value: ";
// getting input 
  cin>>string;
// find length of string with strlen function
  length=strlen(string);
  for(c=0;c<=length;c++)
  {
// if Uppercase range between  65 & 92 then + 32 for Lowercase Range and store in String
    if(string[c]>=65 && string[c]<91)
    {
string[c]=string[c]+32;
    }
  }
// Display lower case String
  cout<<"String in Lowecase = "<<string<<endl;
  return 0;
}

Output: