C++ Console Even/Odd Control Without %,/,+ and -

[Sikkirigi]

Hi everyone I need to write that console program but I don't have any idea how. Can anybody help?

[2kaud]

Well a good starting point would to be explain in more detail what you are trying to achieve and the problem you are encountering so that we can provide guidance.

If you are referring to your previous post here http://forums.codeguru.com/showthrea...t=#post2189745

then from the provided guidance with what are still having problems?

[Sikkirigi]

It is unrelated to my previous topic. I need to write a console program that tells the input is odd or even. But I don't have the knowledge to write it. I guess it can be done with using strings, but I couldn't write it.

[laserlight]

I need to write a console program that tells the input is odd or even. But I don't have the knowledge to write it. I guess it can be done with using strings, but I couldn't write it.

"The most important single aspect of software development is to be clear about what you are trying to build." -- Bjarne Stroustrup

Hence, I reiterate 2kaud's point: "explain in more detail what you are trying to achieve and the problem you are encountering". What do you mean by "tells the input is odd or even"? For example, you could provide a few examples of test input, explain what the test input means, then provide the corresponding expected output, explaining how you arrived at the expected output from the input. After that, you can post your best attempt (i.e., code of a small and simple program), along with the actual output that differs from the expected output.

[Ramees219]

It is unrelated to my previous topic. I need to write a console program that tells the input is odd or even. But I don't have the knowledge to write it. I guess it can be done with using strings, but I couldn't write it.

hi i am working on something same like that to . no matter how big the input value is we can find it even or odd from the last value of the input in this case we working on a string and also you can't use (% , / , - , + ) so i use an if statement to find its even or odd
even values =02468 , odd values = 13579


#include <iostream>
#include <string>

using namespace std;

string EvenOdd_Finder(string);

int main(){

// string input
string a = "45215485684587452152";


cout << "this is a "<< EvenOdd_Finder(a) << " value"<< endl;


return 0;

}


string EvenOdd_Finder(string input){

// even and odd char in string
string even = "02468";
string odd = "13579";

// input size -1 to find the last digit
int size = input.size() - 1;

for (int i = 0; i < 5; i++){

if (input[size] == even[i]){

return "even";

}
else if (input[size] == odd[i]){

return "odd";
}
}



}

[2kaud]

When posting code, please use code tags so that it is readable! Go Advanced, select the formatted code and click '#'.

string EvenOdd_Finder( const string& input) {

	// even and odd char in string
	const string even = "02468";
	const string odd = "13579";

	const char lst = *input.crbegin();

	for (int i = 0; i < 5; ++i) {

		if (lst == even[i])
			return "even";

		if (lst == odd[i])
			return "odd";
	}

        return "bad";
}

This is a slightly changed version by first setting lst to the last char of the input string and passing the argument as a const ref rather than by value. It also returns 'bad' if the string doesn't end with a number.

However, the for loop is not needed. Consider

string EvenOdd_Finder(const string& input) {
	const char lst = *input.crbegin();

	if (string("02468").find_first_of(lst) != string::npos)
		return "even";

	if (string("13579").find_first_of(lst) != string::npos)
		return "odd";

        return "bad";
}

and for the masochists consider

string EvenOdd_Finder(const string& input) {
	const char lst = *input.crbegin();
	return (string("02468").find_first_of(lst) == string::npos) ? ((string("13579").find_first_of(lst) == string::npos) ? "bad" : "odd") : "even";
}

[Ramees219]

Thank u for correcting the code i hope u have to do that again

[Sikkirigi]

Thanks a lot for the help, but I received an error while compiling it, what is the problem?

[bcc32 Error] File1.cpp(5): E2108 Improper use of typedef 'string'

[laserlight]

What exactly is the code that you attempted to compile?

[2kaud]

and which compiler are you using? This code is for c++11. If you are using an older compiler that doesn't support some of the newer features, then you'll receive compiler errors.

[Sikkirigi]

I tried this code

string EvenOdd_Finder(const string& input) {
	const char lst = *input.crbegin();

	if (string("02468").find_first_of(lst) != string::npos)
		return "even";

	if (string("13579").find_first_of(lst) != string::npos)
		return "odd";

        return "bad";
}

and that line gave the error

string EvenOdd_Finder(const string& input)

I am using RAD Studio XE8 and I need to make it work on RAD.

[2kaud]

What you posted is just a function, not a complete program. In my post #6 I only provided replacement code for the function, not a complete program. A complete compilable program would be something like

#include <iostream>
#include <string>

using namespace std;

string EvenOdd_Finder(const string&);

int main()
{
	string a = "4521548568458745215a";

	cout << "this is an " << EvenOdd_Finder(a) << " value" << endl;
	return 0;
}

string EvenOdd_Finder(const string& input)
{
	const char lst = *input.crbegin();

	if (string("02468").find_first_of(lst) != string::npos)
		return "even";

	if (string("13579").find_first_of(lst) != string::npos)
		return "odd";

        return "bad";
}

If this doesn't compile then there is an issue with the compiler. However as RAD Studio XE8 is based upon the Clang c++11 compiler, the above should compile and run OK.

[Ramees219]

When a blank string or if a cleared string get error it not showings
Bad why

string a = "h"; return bad
a.clear(): error

[2kaud]

Please would you explain further as this code compiles and executes as expected

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

int main()
{
	string a = "h";
	cout << a << endl;

	a.clear();
	cout << a << endl;
}

[Ramees219]

Sorry my bad . If u pass a value into EvenOdd_Finder like a
string a = "h"; It return bad but if i clear that or it empty it not return bad