Case Changing Program - Need help on last bit

[frozenflame2]

#include <iostream.h>
int main(void){

char a;
char b;

cim >> b;
b=b-'a'+'A';
cout << b;

return 0;

}

I am like about 2 weeks into programming, so I am pretty simplistic in my programs. If you put that into like a Borland Compiler (not sure if other compilers use exact same format) it will change a lower case letter into an upper case letter. That part I have down through a lot of work (lot of work for me b/c I am not really that good at programming). I want to make it so my program can keep going after one.

Basically, right now, I type in a lower case letter after running the program and it becomes upper case. I want it so that after I get an uppercase letter, I can go to a new line and type another lowercase letter which will become uppercase. I do not want to need to re-run the program. I want to be able to type like "a" and get "A" and then automatically get sent to the next line so I can type like "x" and then get "X". The program always terminates after it converts I letter. I am currently like testing while loop restrictions to get it to work, but i have been overall unsuccessful. Also, I want it to terminate if I don't type in a character. Thanks for your help. I have looked at codes that convert letters, but they are very advanced. My code gets the job done, but is very short b/c I can't really do it any other way.

[GreenDay2001]

You could add a simple infinite loop for that, and set a condition that if input character is something other than lower case it would break:

while( 1 ) {
    cin >> b;
    if( (b < 'a') || (b > 'z') )
        break;
    b=b-'a'+'A';
    cout << b;
}

[Ancient Dragon]

use the standard tolower() function (sometimes its a macro) to convert a character to lower case and it will work on every compiler's implementation

b = tolower(b);

[ChaseVoid]

Your program is wrong. iostream.h is not a valid c++ header file, IOSTREAM is.

There is no such thing in C++ as "cim". "cin" is used to input data.

Here I'll give you a code that can change the case of character (assuming that only Alphabets are the input). It'll change the lower to upper and upper to lower.

#include <iostream>
int main(void)
{

char b;
int x = 0;
while ( x < 10 )
{
	std::cout<<"Enter an Alphabet : " ;
	std::cin >> b;

	if (b < 'A' || b > 'Z')
	{
		b = b - 32;
		std::cout << "Lower case : " << b << std::endl;;
	}
	else
	{
		b = b + 32;
		std::cout << "Upper case : " << b << std::endl;
	}
	x++;
}

std::cin.ignore();
std::cin.get();
return 0;

}

Try this out. It'll give the desired result you want. It'll will loop the statements within while 10 times, you can change that as how you please.

[GreenDay2001]

> Your program is wrong. iostream.h is not a valid c++ header file, IOSTREAM is.
Right, but maybe his teacher expects him to use old compilers like Turbo C++, like my syllabus and teacher :)

> loop 10 times
He wants the program to be terminated when user wants, so better we place acondition than loop it exactly 10 times

> b = b + 32; Using this would be better practice b=b-'a'+'A'; Since its not necessary that you use ASCII character encoding always.

[Narue]

>Using this would be better practice b=b-'a'+'A'; Since its not
>necessary that you use ASCII character encoding always.
You're splitting hairs when there's no difference at all. Both solutions are non-portable and rely on the setup of the ASCII character set. The latter is a better choice only because it avoids magic numbers.

[GreenDay2001]

>Using this would be better practice b=b-'a'+'A'; Since its not
>necessary that you use ASCII character encoding always.
You're splitting hairs when there's no difference at all. Both solutions are non-portable and rely on the setup of the ASCII character set. The latter is a better choice only because it avoids magic numbers.

Ok got it. I reckon standard function in ctype, would be the best practice. But, is there any way to implement a portable function for this??

[Narue]

>But, is there any way to implement a portable function for this??
If you only allow the basic C++ character set, sure:

namespace {
  const char *upper = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
  const char *lower = "abcdefghijklmnopqrstuvwxyz";
}

int convert_char ( int c, const char *from, const char *to )
{
  int i = 0;

  while ( from[i] != '\0' && from[i] != c )
    ++i;

  if ( from[i] == '\0' )
    return c;

  return to[i];
}

int to_upper ( int c )
{
  return convert_char ( c, lower, upper );
}

int to_lower ( int c )
{
  return convert_char ( c, upper, lower );
}