Computer Science Question: Help me to clear string i c/c++

akmal_crazy

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Date Posted: 7/24/2008 1:10:57 AM Status: Live

Help me to clear string i c/c++

Course	Textbook	Chapter	Problem
Software Design	C++: How to Program (5th) by Deitel, Deitel, Deitel	N/A	N/A

Question Details:

Dear seniours

Please guide me about the header file <string.h>

and the keyword string

is it the replacement for defining the character array

and where we use it

give me appropriate e.g.

please reply soon as possibe

Thankx

The <string.h> Header File

This is the ISO C standard header file for string and memory manipulation. This includes ascii strings and memory strings. Not yet all the standard functions of this header file are supported. If a declaration is present in the supplied header file, then uCR supports it and will continue to support it. If a function is not there, it will be added in time.

This header file defines several functions to manipulate C strings and arrays.

Concatenation:

strcat

Concatenate strings (function)

strncat

Append characters from string (function)

Comparison:

memcmp Compare two blocks of memory (function)

strcmp Compare two strings (function)

strcoll Compare two strings using locale (function)

strncmp Compare characters of two strings (function)

strxfrm Transform string using locale (function)

Searching:

memchr Locate character in block of memory (function)

strchr Locate first occurrence of character in string (function)

strcspn Get span until character in string (function)

strpbrk Locate character in string (function)

strrchr Locate last occurrence of character in string (function)

strspn Get span of character set in string (function)

strstr Locate substring (function)

strtok Split string into tokens (function)

Other:

memset Fill block of memory (function)

strerror Get pointer to error message string (function)

strlen Get string length (function)

STRING:

One of the most useful data types supplied in the C++ libraries is the string. A string is a variable that stores a sequence of letters or other characters, such as "Hello" or "May 10th is my birthday!". Just like the other data types, to create a string we first declare it, then we can store a value in it. Strings in C++ are fairly similar to strings in Java, but there are also some important differences. Below, we provide a brief overview of using strings in C++.

We can declare strings and assign literal values to them as follows:

string testString;
testString = "This is a string.";

We can combine these two statements into one line:

string testString = "This is a string.";

Often, we use strings as output, and cout works exactly like one would expect:

cout << testString << endl;

will print the same result as

cout << "This is a string." << endl;

In order to use the string data type, the C++ string header file must be included at the top of the program. Also, you’ll need to include genlib.h to make the short name string visible instead of requiring the cumbersome std::string. (As a side note, std is a C++ namespace for many pieces of functionality that are provided in standard C++ libraries. For the purposes of this class, you won't need to know about namespaces.) Thus, you would have the following

#include's in your program in order to use the string type.

Example:

#include <iostream>
#include <string>
using namespace std;

int main ()
{
    char *line = "short line for testing";

    // with no arguments
    string s1;
    s1 = "Anatoliy";
    cout << "s1 is: " << s1 << endl;

    // copy constructor
    string s2 (s1);
    cout << "s2 is: " << s2 << endl;

    // one argumen
    string s3 (line);
    cout << "s3 is: " << s3 << endl;

    // first argumen C string
    // second number of characters
    string s4 (line,10);
    cout << "s4 is: " << s4 << endl;

    // 1 - C++ string
    // 2 - start position
    // 3 - number of characters
    string s5 (s3,6,4); // copy word 'line' from s3
    cout << "s5 is: " << s5 << endl;

    // 1 - number characters
    // 2 - character itself
    string s6 (15,'*');
    cout << "s6 is: " << s6 << endl;

    // 1 - start iterator
    // 2 - end iterator
    string s7 (s3.begin(),s3.end()-5);
    cout << "s7 is: " << s7 << endl;

    // you can instantiate string with assignment
    string s8 = "Anatoliy";
    cout << "s8 is: " << s8 << endl;

    return 0;
}

Help me to clear string i c/c++

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Answers:

The <string.h> Header File