string array search

**Svetlin** · 11-23-2010

Hi to all C++ programmers, I am at collage and studding computer science. I have problem to solve but my code have a error. Basically I have to read a file with 1000 boys and girls names being ranked , load them in to arrays and then after user type a name the program have to search those arrays and find the name and display it along with its ranking. File:
1 Jacob Emily
2 Michael Emma
3 Joshua Madison
4 Matthew Olivia
5 Ethan Hannah
6 Andrew Abigail
7 Daniel Isabella
8 William Ashley
9 Joseph Samantha
10 Christopher Elizabeth

When I compile my code assigning tagetName as char it compiles but no output, when I assign it as string it gives error that it can transfer int to char in that line ; if(targetName == boys[i])
I am caind of stcuk at this point, I will be thankfull if someone can give me some tip or if I need to change the way I have done the code.
Thanks
code:

Code:

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

int main( )
{
	char boys[1000], girls[1000];
	int count = 0, boyRank = 0, girlsRank = 0, num;
	char targetName[16];
cout <<"Type name to search\n";
cin >> targetName;

	ifstream inFile;
	inFile.open ("babynames2004.txt");

		if (inFile.fail( )) 
		{ 
			cout << "Input file opening failed.\n"; 
			exit(1); 
		} 

while(! inFile.eof( ))
{
	inFile >> num;
	inFile >> boys[count];
	inFile >> girls[count];
	count++;
}
for (int i = 0; i < 1000; i++)
{
	{
	if(targetName == boys[i])
		boyRank = i+1;
	break;
    }
	{
	if(targetName == girls[i])
		girlsRank = i+1;
	break;
	}
}
    if(boyRank != 0 && girlsRank !=0)
cout << targetName <<" is ranked "<< boyRank <<"among boys.\n";
cout << targetName <<" is ranked "<< girlsRank <<"among girls.\n";
	else if(boyRank != 0 && girlsRank = 0)
cout << targetName <<" is ranked "<< boyRank <<"among boys.\n";
cout << targetName <<" is not ranked among to 1000 girl names.\n";
	else if(boyRank = 0 && girlsRank != 0)
cout << targetName <<" is ranked "<< girlsRank <<"among girls.\n";
cout << targetName <<" is not ranked among to 1000 boy names.\n";
	return 0;
}

**Dino** · 11-23-2010

You need a 2D array to hold an array of names. One dimension is the number of names (1,000 in this case) and the other dimension is the max length (+1) you expect for a name.

**Svetlin** · 11-24-2010

I am not allowed to use 2d arr at this point, any way I found the problem, it was in the declaration of targetname and my brackets of the if loops were off place, working now.

**hk_mp5kpdw** · 11-24-2010

#1

Code:

while(! inFile.eof( ))
{
	inFile >> num;
	inFile >> boys[count];
	inFile >> girls[count];
	count++;
}

Don't use end-of-file testing to control a loop in such a way. Instead it should be this:

Code:

while(count < 1000 && inFile >> num boys[count] >> girls[count])
{
	count++;
}

When your last line is read from the file, the eof test will still return false and you will therefore enter the loop even though you're at the physical end of file. Once you're in the loop it's already too late. Your code is already attempting to process data... the reads at this point would fail since there is no more to read but you still increment count and so when the loop does then exit your code is likely in a state where you're left thinking that there is one more element than there truly is (provided you actually used the count variable in such a way... see #2 below).

The code above effectively tests the state of the stream (inFile) as it attempts to read from the file. Any problems encountered during this read will cause this test to return false and cause the loop to exit.

The count < 1000 part makes sure that you stop after reaching 1000 names since your array cannot handle more than that number. Otherwise you run the risk of a crash because you overrun the bounds of your arrays.

#2

Code:

for (int i = 0; i < 1000; i++)
{
	{
	if(targetName == boys[i])
		boyRank = i+1;
	break;
    }
	{
	if(targetName == girls[i])
		girlsRank = i+1;
	break;
	}
}

You have this handy count variable that has the number of records read, you don't need to search through more array slots than you have values read from the file. No point searching 1000 array elements if you've only read 10 rows from the file... it's inefficient.

**Svetlin** · 11-25-2010

Hi, thanks for the fast response, actually this 10 rows are only 10 of 1000 rows I have in a file, that’s way I have the 1000, but you were right for the < 1000 part, it fixed one of the critical errors. Working now after some more changes…

**Xupicor** · 11-25-2010

I was just wondering why not to use std::vector of std::strings here?

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