how to get string length in c 2b 2b

1// string::length
2#include <iostream>
3#include <string>
4
5int main ()
6{
7  std::string str ("Test string");
8  std::cout << "The size of str is " << str.length() << " bytes.\n";
9  return 0;
10}

1str.length();

1#include <iostream>
2#include <string>
3
4int main()
5{
6  string str = "iftee";
7  
8  //method 1: using length() function
9  int len = str.length();
10  cout << "The String Length: " << len << endl;
11  
12  //method 2: using size() function
13  int len2 = str.size();
14  cout << "The String Length: " << len2 << endl;
15  
16  return 0;
17}

1#include <string>
2#include <iostream>
3
4int main()
5{
6    std::string s(21, '*');
7
8    std::cout << s << std::endl;
9
10    return 0;
11}
12

1
2  string txt = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
3cout << "The length of the txt 
4  string is: " << txt.length(); 
5  
6//Tip: You might see some C++ programs that use the size() function to get the length of a string. This is just an alias of length(). 
7//It is completely up to you if you want to use length() or size():
8  
9  string txt = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
10cout << "The length of the txt string is: " << txt.size();

1#include <iostream>
2#include <cstring>
3using namespace std;
4
5int main() {
6
7  // initialize C-string
8  char song[] = "We Will Rock You!";
9
10  // print the length of the song string
11  cout << strlen(song);
12
13  return 0;
14}
15
16// Output: 17