Check out example codes for "is it len function is aviable for c+=". It will help you in understanding the concepts better.

Code Example 1

#include<iostream>
#include<cstring>
using namespace std;
main() {
   string myStr = "This is a sample string";
   char myStrChar[] = "This is a sample string";
   cout << "String length using string::length() function: " << myStr.length() <<endl;
   cout << "String length using string::size() function: " << myStr.size() <<endl;
   cout << "String length using strlen() function for c like string: " << strlen(myStrChar) <<endl;
   cout << "String length using while loop: ";
   char *ch = myStrChar;
   int count = 0;
   while(*ch != '\0'){
      count++;
      ch++;
   }
   cout << count << endl;
   cout << "String length using for loop: ";
   count = 0;
   for(int i = 0; myStrChar[i] != '\0'; i++){
      count++;
   }
   cout << count;
}

Code Example 2

str.length();

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