How to move the file pointer to next character through "ifstream" without "getting" any character, just like "fseek" does?

Question

seekg uses ios as the second argument, and ios can be set to end or beg or some other values as shown here: http://www.cplusplus.com/reference/iostream/ios/

I just want the pointer to move to the next character, how is that to be accomplished through ifstream?

EDIT Well, the problem is that I want a function in ifstream similar to fseek, which moves the pointer without reading anything.

Solution 1

ifstream fin(...);
// ...

fin.get(); // <--- move one character
// or
fin.ignore(); // <--- move one character

Solution 2

Yes. Its called seekg() as you seem to already know?

std::ifstream is("plop.txt" );

// Do Stuff

is.seekg (1, std::ios::cur);  // Move 1 character forward from the current position.

Note this is the same as:

is.get();

// or 

is.ignore();

Solution 3

Read the docs for seekg and use ios_base::cur as indicated there.

Comments

[Aquarius_Girl]

Thanks, but if I use the "ignore" will that effect the getline function which I want to use with pointer set to the next character? I mean will the ignored character be read by the getline then?

[Aquarius_Girl]

Thanks again, but the doc says current position within sequence. And how is that going to move the pointer? I couldn't get the point.

[Aquarius_Girl]

I feared that! I want it to be read by the getline. I just want the pointer to be moved without "getting" anything.

[Mat]

The docs says "current position in the stream buffer". With an offset of one and ::cur, you'll move one byte forward.

[Aquarius_Girl]

Let me try that and see what happens.

[Yakov Galka]

@Anisha: but that's impossible, getting is reading from the current position of the pointer! Maybe you should post what your problem is and ask for a proper solution.

[Martin York]

@Anisha Kaul: When you move the pointer with seek or get or ignore you are moving the position of the pointer from which the next read will take place. You are in affect reading the next character (or moving over it) to set the position from which a read will take place. Explain the real problem. Your edit is explaining the solution you want to a problem that we don't understand. If you explain the real problem, what problem are you trying to solve that requires you to move forward one character, maybe we can suggest a better solution. i.e. we need more context.

[code_dredd]

Is there something else to this? I've used std::ostream &s to do s.seekp(-2, std::ios_base::cur); in order to overwrite the last two chars by immediately doing s << ">]";, but the last 2 chars that should be overwritten (1 comma + 1 space) are still there and not overwritten; the ">]" chars do not show up in the stream..