Phone DB app c++

[denver2020]

I need that name to be displayed based on search string. For example if the Phone DB has a name "Tenzin John" and if I type only the first or last full name, it returns the name. But if I search by string like "Te" or "Jo" matching strings, nothing gets displayed. This string matching must not be case sensitive.

Below is my code, but it doesn't work as expected.

void SearchforNames(string Names[], int total, string UserInput, vector<string> &First, vector<string> &Last) 
{
	int pos;
	int spos;			 	
	for (int i = 0; i < total; ++i)
	{
		
		pos = Names[i].find(UserInput);

		spos = Names[i].find(" ");
			
		// If pos == -1 than continue, name isn't in the list.
		if( pos == -1)
		{
			continue; 
		}
		
		// If pos != -1 than the name is found.
		else  
		{
		}
					
		}

		// If pos < spos, then it's a last, push into vector.
		if( pos < spos)
		{   
		    int i;
		    Last.push_back(Names[i]);	
		}
		int i;
		int pos2 = Names[i].find(spos, UserInput);
		if( pos2 > spos)
		{
			First.push_back(Names[i]);
		}
		if( pos > spos)
		{
			 First.push_back(Names[i]);
		}									 
}

[thmm]

if( pos == -1)

Where did you get this idea that find would return -1 ??????

[mbozzi]

Where did you get this idea that find would return -1 ??????

It's guaranteed that
std::string::npos == std::numeric_limits<std::size_t>::max() == std::size_t(-1)
So (this part of the code) is correct, if awful.

[jonnin]

is it awful? Its ensured so you can do exactly that, or am I off base? Otherwise, why define a value for it at all: force them to use the wordy text every single time.

[mbozzi]

Yeah I guess it's not so bad.

[JLBorges]

C++11:

#include <string>
#include <regex>
#include <vector>
#include <iostream>

// looks for case-insensitive matches for beginning of first names, last names
// invariant: names are of the form first_name white space last_name ie. ^\S+\s+\S+$, user_input is alphanumeric
void search_for_names( const std::string names[], std::size_t num_names, std::string user_input,
                       std::vector<std::string>& matched_first_names, std::vector<std::string>& matched_last_names )
{
    const std::regex first_name_re( user_input + ".*",  std::regex::icase ) ; // begins with user_input
    std::regex last_name_re( "\\S+\\s+" + user_input + ".*",  std::regex::icase ) ; // second name begins with user_input

    matched_first_names.clear() ;
    matched_last_names.clear() ;

    // if( user_input.empty() ) return ; // uncomment if empty input does not match the beginning of any string

    for( std::size_t i = 0 ; i < num_names ; ++i )
    {
        if( std::regex_match( names[i], first_name_re ) ) matched_first_names.push_back( names[i] ) ;
        if( std::regex_match( names[i], last_name_re ) ) matched_last_names.push_back( names[i] ) ;
    }
}

int main() // a minimal test driver
{
    std::string names[] = { "Bugs Bunny", "Daffy Duck", "PORKY   Pig", "pig porky", "Elmer Fudd", "Daft Daffodil", "Coy coyote", "Wile Coyote" } ;
    const std::size_t N = sizeof(names) / sizeof(*names) ;

    for( const std::string input : { "BUN", "bu", "daf", "pork", "udd", "COY", "" } )
    {
        std::cout << "input: \"" << input << "\"\n" ;

        std::vector<std::string> first_names ;
        std::vector<std::string> last_names ;

        search_for_names( names, N, input, first_names, last_names ) ;

        std::cout << '\t' << first_names.size() << " #matching first name\n" ;
        if( !first_names.empty() ) for( const std::string& name : first_names ) std::cout << "\t\t" << name << '\n' ;
        std::cout << '\t' << last_names.size() << " #matching last name\n" ;
        if( !last_names.empty() ) for( const std::string& name : last_names ) std::cout << "\t\t" << name << '\n' ;
        std::cout << "-------------\n" ;
    }
}

http://coliru.stacked-crooked.com/a/742619e311b050d8

[thmm]

is it awful? Its ensured so you can do exactly that, or am I off base? Otherwise, why define a value for it at all: force them to use the wordy text every single time.

Magic numbers are a code smell, though for simple homework it's probably not a big deal.