Programming Forums > Application Development > C++

357mag · Jun 7th, 2007, 12:03 AM

I've got this program that compares two words. Later on it changes the case of a word from uppercase to lowercase. I saw someplace on the web where a guy was doing this:

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string lowerOrangeFruit = ConvertToLowerCase(orangeFruit)

He was including some header file called "strutils.h" and "genlib.h"

I tried it in my program but my compiler says no way.

Here is what I'm trying to do:

(Toggle Plain Text)

int main()
{
	string guitar = "guitar"; // g has an ASCII code of 103
	string piano = "Piano"; // P has an ASCII code of 80

	cout << "Does " << guitar << " come before " << piano << "?" << endl << endl;

	if (guitar < piano)
		cout << "Yes!";

	else
	    cout << "No!";

	string lowerPiano = string.tolower(piano);

	return 0;
}

But I'm doing something wrong. I sense that it must be a pretty easy fix. I'll have to keep monkeying around with it.

DaWei · Jun 7th, 2007, 7:28 AM

Decase your words a char at a time (loop on word length) using tolower () or toupper ().

Infinite Recursion · Jun 7th, 2007, 8:31 AM

(Toggle Plain Text)

string MyToLower (string source)
{
   int i = 0;
   string temp = "";
   for (i=0;i <= source.length()-1; i++)
   {
      temp = temp + (char)(tolower(source[i]));
   }
   return temp;
}

....

string lowerPiano = MyToLower(piano);

DaWei · Jun 7th, 2007, 9:35 AM

or, more efficiently (no function call in the loop):

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...
    int len = source.length ();
    for (i = 0; i < len; ++i)
...

Cache · Jun 7th, 2007, 9:50 AM

or, using the tools already provided by the standard:

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#include <cctype>
#include <string>
#include <algorithm>

// ...

std::string str = "ABCDE";
std::transform(str.begin(), str.end(), str.begin(), std::tolower);

Infinite Recursion · Jun 7th, 2007, 11:13 AM

ooops, i should probably take the time to optimize the code in my lil' lib one day.

DaWei · Jun 7th, 2007, 12:52 PM

LOL, I don't really call it optimization. When I optimize, I put an analyzer on the thang and get a good profile. It just comes from being old and having to deal with 2K-256K of memory and a 1MHz-8MHz clock. One whittled as they went, and if it still didn't woik, they got serious and whittled some more. Mailpieces and such, moving at 100-400 inches per second, wait on no man to collect the data and decide when to divert their path.

Jun 7th, 2007, 12:03 AM	#1
357mag Hobbyist Programmer Join Date: Mar 2005 Posts: 148 Rep Power: 4	Converting a word to lower case I've got this program that compares two words. Later on it changes the case of a word from uppercase to lowercase. I saw someplace on the web where a guy was doing this: (Toggle Plain Text) string lowerOrangeFruit = ConvertToLowerCase(orangeFruit) string lowerOrangeFruit = ConvertToLowerCase(orangeFruit) He was including some header file called "strutils.h" and "genlib.h" I tried it in my program but my compiler says no way. Here is what I'm trying to do: (Toggle Plain Text) int main() { string guitar = "guitar"; // g has an ASCII code of 103 string piano = "Piano"; // P has an ASCII code of 80 cout << "Does " << guitar << " come before " << piano << "?" << endl << endl; if (guitar < piano) cout << "Yes!"; else cout << "No!"; string lowerPiano = string.tolower(piano); return 0; } int main() { string guitar = "guitar"; // g has an ASCII code of 103 string piano = "Piano"; // P has an ASCII code of 80 cout << "Does " << guitar << " come before " << piano << "?" << endl << endl; if (guitar < piano) cout << "Yes!"; else cout << "No!"; string lowerPiano = string.tolower(piano); return 0; } But I'm doing something wrong. I sense that it must be a pretty easy fix. I'll have to keep monkeying around with it.

Jun 7th, 2007, 7:28 AM	#2
DaWei Resident Grouch Join Date: Jun 2005 Posts: 6,453 Rep Power: 10	Decase your words a char at a time (loop on word length) using tolower () or toupper (). __________________ Abstraction doesn't make it impossible to write bad code; it makes it possible to write superior code. Contributor's Corner: Grumpy on C++ Exceptions DaWei on Pointers

Jun 7th, 2007, 8:31 AM	#3
Infinite Recursion Programming Guru Join Date: Jul 2004 Location: United States Posts: 3,467 Rep Power: 8	(Toggle Plain Text) string MyToLower (string source) { int i = 0; string temp = ""; for (i=0;i <= source.length()-1; i++) { temp = temp + (char)(tolower(source[i])); } return temp; } string MyToLower (string source) { int i = 0; string temp = ""; for (i=0;i <= source.length()-1; i++) { temp = temp + (char)(tolower(source[i])); } return temp; } .... string lowerPiano = MyToLower(piano); __________________ http://jasonpowers.net "There are a thousand hacking at the branches of evil to one who is striking at the root."

Jun 7th, 2007, 9:35 AM	#4
DaWei Resident Grouch Join Date: Jun 2005 Posts: 6,453 Rep Power: 10	or, more efficiently (no function call in the loop): (Toggle Plain Text) ... int len = source.length (); for (i = 0; i < len; ++i) ... ... int len = source.length (); for (i = 0; i < len; ++i) ... __________________ Abstraction doesn't make it impossible to write bad code; it makes it possible to write superior code. Contributor's Corner: Grumpy on C++ Exceptions DaWei on Pointers

Jun 7th, 2007, 9:50 AM	#5
Cache Hobbyist Join Date: Sep 2005 Posts: 261 Rep Power: 4	or, using the tools already provided by the standard: (Toggle Plain Text) #include <cctype> #include <string> #include <algorithm> // ... std::string str = "ABCDE"; std::transform(str.begin(), str.end(), str.begin(), std::tolower); #include <cctype> #include <string> #include <algorithm> // ... std::string str = "ABCDE"; std::transform(str.begin(), str.end(), str.begin(), std::tolower);

Jun 7th, 2007, 11:13 AM	#6
Infinite Recursion Programming Guru Join Date: Jul 2004 Location: United States Posts: 3,467 Rep Power: 8	ooops, i should probably take the time to optimize the code in my lil' lib one day. __________________ http://jasonpowers.net "There are a thousand hacking at the branches of evil to one who is striking at the root."

Jun 7th, 2007, 12:52 PM	#7
DaWei Resident Grouch Join Date: Jun 2005 Posts: 6,453 Rep Power: 10	LOL, I don't really call it optimization. When I optimize, I put an analyzer on the thang and get a good profile. It just comes from being old and having to deal with 2K-256K of memory and a 1MHz-8MHz clock. One whittled as they went, and if it still didn't woik, they got serious and whittled some more. Mailpieces and such, moving at 100-400 inches per second, wait on no man to collect the data and decide when to divert their path. __________________ Abstraction doesn't make it impossible to write bad code; it makes it possible to write superior code. Contributor's Corner: Grumpy on C++ Exceptions DaWei on Pointers

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Programming Forums > Application Development > C++

Converting a word to lower case