The C++ data(), length(), strlen() and c_str() program example

 

Compiler: Visual C++ Express Edition 2005

Compiled on Platform: Windows XP Pro SP2

Header file: Standard

Additional library: none/default

Additional project setting: Set project to be compiled as C++

Project -> your_project_name Properties -> Configuration Properties -> C/C++ -> Advanced -> Compiled As: Compiled as C++ Code (/TP)

Other info: none

To do: Using the C++ basic_string member functions: data(), length(), strlen() and c_str() in C++ programming

To show: How to use the C++ basic_string class member functions: data(), length(), strlen() and c_str() in C++ programming

 

// the C++ data(), length(), strlen() and c_str() program example

#include <string>

#include <iostream>

using namespace std;

 

int main(void)

{

string str1("Testing the data()");

cout<<"str1 string object is: "<<str1<<endl;

cout<<"Operation: str1.length()"<<endl;

cout<<"The length of str1 = "<<unsigned int(str1.length())<<endl<<endl;

 

// converting a string to an array of characters

const char *ptr1 = 0;

ptr1= str1.data();

cout<<"Operation: str1.data()"<<endl;

cout<<"The modified ptr1 string object is: "<<ptr1<<endl;

cout<<"Operation: strlen(ptr1)"<<endl;

cout<<"The length of character array str1 = "<<unsigned int(strlen(ptr1))<<endl<<endl;

 

// converting a string to a C-style string

const char *cstr1 = str1.c_str();

cout<<"Operation: str1.c_str()"<<endl;

cout<<"The C-style string c_str1 is: "<<cstr1<<endl;

cout<<"Operation: strlen(ptr1)"<<endl;

cout<<"The length of C-style string str1 = "<<unsigned int(strlen(cstr1))<<endl;

return 0;

}

 

Output example:

 

str1 string object is: Testing the data()

Operation: str1.length()

The length of str1 = 18

 

Operation: str1.data()

The modified ptr1 string object is: Testing the data()

Operation: strlen(ptr1)

The length of character array str1 = 18

 

Operation: str1.c_str()

The C-style string c_str1 is: Testing the data()

Operation: strlen(ptr1)

The length of C-style string str1 = 18

Press any key to continue . . .

 

 

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