C++. 1Class with changing parameters - c++

Question

I've got a class with 3 private variables and one public method, that has 2 char parameter variables.
class InitLine
{
private:
char *a;
char b, c;
public:
InitLine(char *inita, char initc);
Init(char *a, char c);
};
Now the definition of the method is simple:
Initline::Init(char *a, char c)
{
for (b=0; b<c; b++)
*(a+c)=0;
}
Now my question is: If I wish to repeat the same actions with different parametertypes (*a and c, or one of them becomes an integer e.g.), is it necessary to create a new class, or can I use the existing one, doing some 'typecasting' or some other trick I don't know yet?
Thanks and regards
Uwe

Answer 1

Use templates, make the Init function a template of your arguments type.
template <typename T>
Init(char*a , T c){}
for instance

Answer 2

You have many places in your code, which should be fixed prior to any further operations.
Naming convention is terrible. What is a, b, c?
You use b as a loop indexer, while a local variable should be used there instead.
You don't show us, what is a. Where is it allocated? What is the size of memory pointed to by a?
I guess, that your code should look like the following:
class InitLine
{
private:
char * data;
int count;
public:
InitLine(char * newData, int newCount)
{
// Possible error checking?
data = newData;
count = newCount;
}
// No parameters needed here, I guess
void Init()
{
for (int i = 0; i < count; i++)
data[i] = 0;
}
};
As for your question, I'm not really sure, what you are trying to achieve and what do you want to know. If you want to write a generic class holding any type of arrays, you have to use templates:
template <typename T>
class InitLine
{
private:
T * data;
int count;
public:
InitLine(T * newData, int newCount)
{
// Possible error checking?
data = newData;
count = newCount;
}
// No parameters needed here, I guess
void Init()
{
for (int i = 0; i < count; i++)
data[i] = 0;
}
};
You have to use this class in the following way:
InitLine<char> line(myData, myDataSize);
// where myData is a char * and myDataSize is an int
If you want to write a few methods differing by their parameters, this technique is called method overloading and is available in C++:
void Init(char * a, int b) { /* sth */ }
void Init(int * a, int b) { /* sth */ }
Note, that compiler must be able to clearly distinguish, which method should be called. Eg.
void Test(int a) { }
void Test(char a) { }
Test(0); // Ambiguity: which method should be called?
These are only things coming to my mind, while reading your question. If it is not what you are asking for, consider editing the question to be more specific.

Answer 3

If you just want to have the whole class with different types (not just the Init), e.g. also have int *a; int b,c; then template classes are the other trick you don't know yet.
template <typename ANYTYPE> class InitLine
{
private:
ANYTYPE *a;
ANYTYPE b, c;
public:
void InitLine(ANYTYPE *inita, ANYTYPE initc);
void Init(ANYTYPE *a, ANYTYPE c);
};
template <typename ANYTYPE> void Initline<ANYTYPE>::Init(ANYTYPE *a, ANYTYPE c)
{
for (int b=0; b<c; b++)
*(a+c)=0;
}
... main()
{
Initline<int> iline; // initline class based on type int (ANYTYPE -> int)
int line[20];
Initline<char> cline; // initline class based on type char (ANYTYPE -> char)
char somechars[30];
iline.Init(line, 20);
cline.Init(somechars, 30);