Seekp() function in C++
What is Seekp() function?
A member function of the ostream class in the C++ standard library is seekp(). It sets the put pointer's location within an output stream. The put pointer shows the position where the following character will be written in the stream.
Syntax:
ostream& seekp(streampos pos);
ostream& seekp(streamoff off, ios_base::seekdir dir);
pos: It is used to determine a stream's exact position.
off: It indicates an offset that shifts the put pointer about a particular direction.
dir: It outlines the direction the offset will be applied from the reference point. Any of the following values could represent it:
Constant | Explanation |
beg | Beginning of a stream |
cur | Current position of a put pointer |
end | End of a stream |
Example:
ios_base::beg
ios_base::cur
ios_base::end
Return value:
The return value is the reference to the ostream object on which seekp() was called. You can link together different stream actions in this way.
Example program:
//Seekp() function in C++
#include <iostream>
#include <fstream>
using namespace std;
int main() {
ofstream jtp("jtp.txt");
if (jtp.is_open()) {
jtp << "This is JTP Platform.";
// Get the current position
streampos position = jtp.tellp();
// Set the put pointer to position 8
jtp.seekp(8);
jtp<< "JAVA T POINT";
// Close the file
jtp.close();
// Read and print the file contents
ifstream readjtp("jtp.txt");
string line;
if (readjtp.is_open()) {
while (getline(readjtp, line)) {
cout << line << '\n';
}
readjtp.close();
} else {
cout << "cannot be open.\n";
}
} else {
cout << "cannot be create.\n";
}
return 0;
}
Explanation:
This program creates a file called "jtp.txt" and inserts the text "This is JTP Platform." into it as its first line. After that, the put pointer is set to position 8 using seekp(), "JTP" is replaced with "JAVA T POINT", and the original position is restored using the streampos that were previously saved. After that, we shut the file and examined its data to ensure the modifications were made.
Output:
![seekp() function in C++](https://static.tutorialandexample.com/cpp/seekp-function-in-cpp1.png)
Advantages of Seekp() function:
In C++, the seekp() method offers several benefits and flexibility when dealing with output streams. The use of seekp() has the following benefits:
Data overwriting or insertion: You can replace or enclose data at a particular location in the output stream by setting the put pointer using seekp(). It is especially helpful if you wish to change the data being written to a stream or the contents of a file. By moving the put pointer to the required spot and then writing new data, you can replace or insert material there.
In search of about current position: You can seek the put pointer's current position using the seekp() function. You can move the put pointer from its present place ahead or backward by supplying a positive or negative offset. It allows you to traverse the stream without performing any absolute position.
Positioning the put pointer: The put pointer can be moved around an output stream using the seekp() function. Due to this, you can choose where the next character will be written. According to your demands, you can use it to shift the put pointer to a certain place in the stream, like the start, the current position, or the finish.
Support for numerous output stream types: seekp() is a member function of the ostream class, which serves as the base class for ofstream, ostringstream, and stringstream, among other output stream types. It allows you to work with files, strings, or other sorts of output streams by allowing you to use seekp() with various output stream objects.
Chaining stream operations: The ability to chain stream operations is provided by referencing the output stream object that seekp() returns. It may result in code that is shorter and easier to read. For instance, one statement can set the put pointer using seekp() and then immediately write data to that position.
Data Insertion: In addition to overwriting data, seekp() allows you to add new data to any location you like within a file. You can move the existing data or insert content between existing data points by moving the write pointer and writing new data. It is quite helpful when working with structured data files, where data needs to be entered at certain spots.
Efficient File Operations: Using seekp() to seek a specific place before conducting write operations can be more effective when working with huge files than rewriting the entire file. It improves efficiency and minimizes I/O operations by allowing you to immediately access the necessary location and alters or inserts data without reading or rewriting the full file.
Handling Binary Files: When working with binary files, where data is stored in a particular format, seekp() is very useful. You can travel to a specific location within the file and write binary data there directly to ensure proper binary data storage without changing the remainder of the file.
File Position Control: seekp() method is used to control the position of the write pointer within a file. After that, you can relocate the pointer to that spot in the file and perform write operations from there. You can read, edit, or add data to the file at any desired place because it allows for random access, which allows for this.
Generally speaking, the seekp() method gives you freedom and control over file write operations, enabling you to quickly change the content of files at certain locations, perform random access, and streamline file handling for faster performance.
Disadvantages of seekp() function:
The seekp() method in C++ has several benefits, but there are a few potential drawbacks you should be aware of as well:
Limited Portability: Depending on the system and file type, seekp() may behave differently and have different restrictions. In some situations or systems, searching to specified points within a file might not be possible or supported. If you significantly rely on seekp() for file manipulation, it may reduce the portability of your code.
Code complexity and readability: Overusing or improperly using seekp() might make it easier to comprehend and maintain your code. It can be more challenging for other developers to comprehend the concept and purpose of the code if the write position is frequently changed.
Complexity: Controlling the position of the write pointer with seekp() makes your code more difficult. When dealing with complicated file structures or numerous concurrent write operations, it necessitates careful monitoring of file locations and offsets, which might be error-prone. Use of seekp() improperly may result in unexpected behavior or damaged file content.
Limited use: Not all file streams or file types may completely use the features offered by seekp().You can set the write position using seekp(), and is not supported by all file streams, including cout and cerr. Additionally, the operating or file systems can impact seekp()'s behavior.
Efficiency Loss for consecutive Writing: Seekp()'s constant movement of the write pointer might cause efficiency losses when used for consecutive write operations. The function is primarily intended for random access and editing of particular file places. Compared to continuous sequential writes, calling seekp() for every write operation when data needs to be written sequentially from the present location can result in more overhead and better performance.
Manipulation of Fragile Files: Carelessly using seekp() method may result in file corruption or other unwanted consequences. Incorrect seek directions or the placement of the write pointer can overwrite crucial information, result in file gaps or overlaps, or data loss. Accurate design and error management are necessary to guarantee the proper behavior and integrity of the file.
Consider whether seekp() is appropriate for your particular use case before employing it by weighing its benefits against these potential drawbacks. In some circumstances, sequential writes or other file manipulation techniques may be more appropriate and effective alternatives.