int to char and vice versa

[mekaj]

Yes, I know I'm a very inexperienced programmer but this is a very simple problem that probably has a very simple solution. I'd appreciate anyone's help!

#include <cstdlib>
#include <iostream>

using namespace std;

int main(int argc, char *argv[])
{
    int number1 = 123;
    char string1 = char(number1);
    
    cout << string1 << endl;    // outputs '2293612'

///////////////////////////////////////
    
    char string2[4] = "123";
    int number2 = int(string2);
    
    cout << string2 << endl;    // outputs '{' because this is the ASCII character "123"
    
    system("PAUSE");
    return EXIT_SUCCESS;
}

In each case I would like the output to be "123." I realize that typecasting won't work. Also, I know I could make an elaborate switch function to get around this but it seems like there must be an easier way. If there is an easy way to do this, could somebody please show me? Thank you very much.

--The struggling C++ student (whose teacher knows nothing)

[SlyMaelstrom]

You can't cast a string like that. Use atoi()

string2[4] = "123";
int number2 = atoi(string2);

cout << number << '\n' << number + 1 << endl;

[mekaj]

Wow, thanks a lot. I had never heard of atoi(). What do I do for the other scenario?

int number1 = 123;
char string1 = char(number1);
    
cout << string1 << endl;    // outputs '2293612'

I should be clear that I intend for the output to be "123"

[SlyMaelstrom]

itoa() works a bit differently.

int main(int argc, char *argv[])
{ 
char string1[4] = "123";
char string2[4];
int number2 = atoi(string1);
itoa(number2,string2,10);  // 10 being for decimal, 2 is binary, 16 is hex

cout << number2 << '\n' << number2 + 1 << '\n' << string2 << endl;

cin.get();
    return EXIT_SUCCESS;

...and for future reference.

atoi() = Alpha to Integer
itoa() = Integer to Alpha

Both of which is found in <cstdlib>

[mekaj]

I can't thank you enough! Finally I won't feel so limited

[jlf029]

#include <cstdlib>
#include <iostream>

using namespace std;


int main()
{
	union convert1
	{
		int number1;
		char string1;
	};
	
	union convert2
	{
		int number2;
		char string2[4];
	};
	
	convert1 test1;
	test1.number1 = 123;
	cout << test1.string1 << endl;
	

///////////////////////////////////////
    
	convert2 test2;
	for(int i=0;i<3;i++)
		test2.string2[i] = i;
	test2.string2[3] = '\0';
	cout << test2.string2 << endl;
	
    

    return 0;
}

[Dave_Sinkula]

http://www.parashift.com/c++-faq-lit....html#faq-39.1
http://www.parashift.com/c++-faq-lit....html#faq-39.2

[SlyMaelstrom]

Stringstreams are nice. You could give those a try. I'm not sure you really need to use unions, though. They're nice, but <sstream> is something you should look into.

[ChaosEngine]

#include <cstdlib>
#include <iostream>

using namespace std;


int main()
{
	union convert1
	{
		int number1;
		char string1;
	};
	
	union convert2
	{
		int number2;
		char string2[4];
	};
	
	
}

sorry, but that's awful. Use stringstreams and if you have a performance problem (streams can be slow), use itoa/atoi.

[jlf029]

heh, i was just being stupid.
Why not just static_cast the variable, you dont need to include any headers.

int number = 65;
cout << static_cast<char>(number) << endl;

[SlyMaelstrom]

The whole point of this guys post is that didn't work.

Did you try compiling the code you just posted? Doesn't quite give you "65" does it.

[jlf029]

my code?
Converting number to char. It compiles fine

[SlyMaelstrom]

It's really like you didn't read the post at all...

He wants the integer 65 to convert to the string "65" and he wants the string "65" to produce the integer 65.

He doesn't want to cast a number and produce it's ascii value.

[Daved]

The itoa function is not standard and may not work on all compilers. Also, the error reporting for atoi is to simply return 0, so you cannot tell if the input was bad or if it was really just "0". String streams are standard and they provide more sophisticated error handling abilities.

Another note- instead of using char, you should be using the C++ string class for strings. They make dealing with strings easier and less error prone. If your teacher doesn't want you to use them for the class for some reason, then you should still consider learning them on your own.