Hi, I need some help with starting a program. Kind of lost on how to begin it, any guide to start it would be helpful.
Here is the link of the program: http://home.earthlink.net/~craie/122/labs/strfind.html
I need to do all the different levels for this program.
Thanks
Here some code to get you started.
int main(){
//your code here
return 0;
}
Post again when you have something in main.
Then people can help with any problems or specific questions about your code.
This (C++) lab will help you practice with C-strings and libraries. Function overloading (in C++) might come in handy, as well.
Two useful functions that are not provided in the standard library (but are with standard C++ string) are find a character in a string and find a substring in a string.
NOTE! These are also provided in C for C strings:
char* p = strchr( str, ch ); // find char ch in str
char* q = strstr( str, findStr ); // findStr in str
So it seems you are to write a 'wrapper' for your class xString that uses a dynamic C string inside the class to hold C strings.
So ... your code can just use the two above C provided functions ... (or you can 'Roll Your Own' - Which IS generally NOT advised!)
If you look at the class String example that I provided for you on an earlier post, you will see there, these examples:
int get_index( char charToFind ); // returns index or -1;
int get_index( const String& strToFind ); // returns index or -1 ... case specific
int get_index_ignore_case( const String& strToFind );
thanks, aside from using the above char functions would I need to create a String class? And say for example if I have the string "I like to program" and if I wanted to find out the position of the t(how would I get a value for that position (7)).
Thanks
Take a look at this simple example ...
/* findCharInString.cpp */
/*
... say for example if I have the string:
"I like to program"
and if I wanted to find out the *INDEX* of the char 't'
how would I get a value for that index = 7 ?
*/
#include <iostream>
#include <string> /* or use your own class String */
#include <cctype> /* re. tolower */
using namespace std;
/* BUT ... better to use C++ library than to 'roll your own' */
int indexCharFoundIn( const string& s, char c )
{
int i;
for( i = s.size() - 1; i >= 0; --i )
{
if( s[i] == c ) break;
}
return i; /* returned value is >= 0 if found, else -1 */
}
/* recall C/C++ char's are stored as integer values ... */
int takeInChar( const string& msg )
{
cout << msg << flush;
string reply;
getline( cin, reply );
if( reply.size() )
return reply[0];
// else ...
return 0;
}
bool more()
{
if( tolower( takeInChar( "\nMore (y/n) ? " )) == 'n' )
return false;
// else ...
return true;
}
int main()
{
do
{
cout << "Enter a line of text: " << flush;
string testLine;
getline( cin, testLine );
cout << "Enter the char to find: " << flush;
char c = cin.get();
while( cin.get() != '\n' ) ; /* 'flush' cin stream ... */
int i = indexCharFoundIn( testLine, c );
if( i != -1 )
cout << "Found at index " << i << endl;
else
cout << c << " was NOT found in " << testLine
<< endl;
}
while( more() ) ;
}
Take a look at this simple example ...
/* findCharInString.cpp */
/*
... say for example if I have the string:
"I like to program"
and if I wanted to find out the *INDEX* of the char 't'
how would I get a value for that index = 7 ?
*/
#include <iostream>
#include <string> /* or use your own class String */
#include <cctype> /* re. tolower */
using namespace std;
/* BUT ... better to use C++ library than to 'roll your own' */
int lastIndexCharFoundIn( const string& s, char c )
{
int i;
for( i = s.size() - 1; i >= 0; --i )
{
if( s[i] == c ) break;
}
return i; /* returned value is >= 0 if found, else -1 */
}
/* recall C/C++ char's are stored as integer values ... */
int takeInChar( const string& msg )
{
cout << msg << flush;
string reply;
getline( cin, reply );
if( reply.size() )
return reply[0];
// else ...
return 0;
}
bool more()
{
if( tolower( takeInChar( "\nMore (y/n) ? " )) == 'n' )
return false;
// else ...
return true;
}
int main()
{
do
{
cout << "Enter a line of text: " << flush;
string testLine;
getline( cin, testLine );
cout << "Enter the char to find: " << flush;
char c = cin.get();
while( cin.get() != '\n' ) ; /* 'flush' cin stream ... */
int i = lastIndexCharFoundIn( testLine, c );
if( i != -1 )
cout << "Last found was at index " << i << endl;
else
cout << c << " was NOT found in " << testLine
<< endl;
}
while( more() ) ;
}
You may also like to see using strchr ... the C string version of finding a char in a C type string?
Note the use of 'pointer arithmetic', when using strchr, to find the index (offset) value of the found char ... if found.
/* findCharInString3.cpp */
/* comparing ...
1. C++ library char find... function
2. C++ 'roll your own char find... function
3. C style char find... function ... (strchr)
*/
#include <iostream>
#include <string> /* C++ string or use your own class String */
#include <cctype> /* re. tolower */
/* Today's C++ uses <cstring> ... and not <string.h> */
#include <cstring> /* re. strchr */
using namespace std;
/* Note: it is considered good style to use C++ library
and not to 'roll your own' functions ... */
int lastIndexCharFoundIn( const string& s, char c )
{
int i;
for( i = s.size() - 1; i >= 0; --i )
{
if( s[i] == c ) break;
}
return i; /* returned value is >= 0 if found, else -1 */
}
/* recall C/C++ char's are stored as integer values ... */
int takeInChar( const string& msg )
{
cout << msg << flush;
string reply;
getline( cin, reply );
if( reply.size() )
return reply[0];
// else ...
return 0;
}
bool more()
{
if( tolower( takeInChar( "\nMore (y/n) ? " )) == 'n' )
return false;
// else ...
return true;
}
int main()
{
do
{
cout << "Enter a line of text: " << flush;
string s;
getline( cin, s );
char c = takeInChar( "Enter the char to find: " );
// using 'roll your own' find... //
int i = lastIndexCharFoundIn( s, c );
if( i != -1 )
cout << "Last " << c
<< " found was at index " << i << endl;
else
cout << c << " was NOT found in " << s << endl;
// using C++ library find... //
size_t pos = s.find_first_of( c );
if( pos != string::npos )
cout << c << " first occured at index "
<< pos << endl;
// using C string library find... //
// firstly, convert C++ string to a (tmp) C string
const char* tmp = s.c_str();
char* p = strchr( tmp, c ); // find char c in tmp C string
if( p ) // if pointer value NOT equal NULL
cout << c << " first occured at index "
<< (p-tmp) << endl; // see pointer arithmetic
}
while( more() ) ;
}
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