The C++ at() member function 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++ at() member function which return a reference to the element at a specified location in the string in C++ programming

To show: How to use the C++ at() member function to return a reference to the element at a specified location in the string in C++ programming

 

// the C++ at() program example

#include <string>

#include <iostream>

using namespace std;

 

int main(void)

{

string str1("Operation"), str2("Desert Storm");

const string constr1("Making cakes"), constr2("Start eating");

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

cout<<"str2 string is: "<<str2<<endl;

cout<<"constr1, const string is: "<<constr1<<endl;

cout<<"constr2, const string is: "<<constr2<<endl;

 

// element access of the non const strings

basic_string <char>::reference RefStr1 = str1[4];

basic_string <char>::reference RefStr2 = str2.at(7);

 

// index starts from 0 lor!

cout<<"\n---str1[5]---"<<endl;

cout<<"The 5th character of str1 is: "<<RefStr1<<endl<<endl;

cout<<"---str2.at(7)---"<<endl;

cout<<"The 7th character of str2 is: "<<RefStr2<<endl<<endl;

 

// element access to the const strings

basic_string <char>::const_reference cRefStr1 = constr1[constr1.length()];

basic_string <char>::const_reference cRefStr2 = constr2.at(8);

cout<<"---constr1.length()---"<<endl;

cout<<"The length of the constr1 string is: "<<unsigned int(constr1.length())<<endl;

cout<<"\nTesting the null character..."<<endl;

cout<<"---cRefStr1 = constr1[constr1.length()]---"<<endl;

cout<<"Operation: (cRefStr1 == \'\\0\')"<<endl;

 

if(cRefStr1 == '\0')

cout<<"The null character is returned."<<endl;

else

cout<<"The null character is not returned."<<endl;

cout<<"\n---constr2.at(8)---"<<endl;

cout<<"The 8th character of the constr2 is: "<<cRefStr2<<endl;

 

return 0;

}

 

Output example:

 

str1 string is: Operation

str2 string is: Desert Storm

constr1, const string is: Making cakes

constr2, const string is: Start eating

 

---str1[5]---

The 5th character of str1 is: a

 

---str2.at(7)---

The 7th character of str2 is: S

 

---constr1.length()---

The length of the constr1 string is: 12

 

Testing the null character...

---cRefStr1 = constr1[constr1.length()]---

Operation: (cRefStr1 == '\0')

The null character is returned.

 

---constr2.at(8)---

The 8th character of the constr2 is: t

Press any key to continue . . .

 

 

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