Kbhit() Function in C
Kbhit() Function in C
Handling keyboard input is crucial for creating interactive console programs or video games in C. The usage of getchar() or scanf(), two common techniques for waiting for user input, might cause issues because they pause program execution until a key is hit. So, to solve this situation, C has the kbhit() function, which saves the day by offering a non-blocking mechanism to determine whether a key has been pressed. In this article, we will look at the kbhit() method, how it works, and why it's important for C programmers.
Let’s discuss the kbhit function in C.
What is Kbhit() function in C?
The kbhit() function is frequently encountered in compilers aimed at Windows systems. With the help of this function, we can check the console to see if a key has been pressed without stopping the program from running. We can build responsive applications that can carry out activities while also waiting for user input by using the kbhit() function.
kbhit() function in C comes under the header file 'conio.h'. It checks whether a key has been pressed or not. We must include the header file "conio.h" in your program in order toutilize the kbhit() function. If a key has been pressed, it returns a value other than zero. Otherwise, it returns nothing.
Note: The kbhit() function in C is not a standard C library.
Let’s see some basic examples to demonstrate this function.
Example:
#include <iostream.h> #include <conio.h> int main() { while (!kbhit()) // kbhit() helps to terminate this loop printf("Press a key\n"); return 0; }
The output of this code is:
Output:
Press a key Press a key Press a key Press a key Press a key
This output differs for every person, and it does not terminate until the user presses any key from the keyboard.
In this example, Once the while loop has started, the program runs continuously until a key is pressed. The !kbhit() condition determines whether a key press has taken place. When a key is pushed, kbhit() produces a non-zero result; hence, using the negation (!) operator in the condition ensures that the loop continues even if no key has been pressed.
Program to fetch the pressed key using kbhit()
This is an application of the kbhit() function. In this case, the programs print the key value, which is pressed by the user, and if the user presses the Escape key, it will terminate the program.
Here is the code for this example:
Example:
#include <stdio.h> #include <conio.h> // This header file is for kbhit function int main() { char ch; printf("Enter ESC key to exit \n"); // Define a loop for entering keys while (1) { if (kbhit) { // fetch typed character into ch ch = getch(); if ((int)ch == 27) // When the ESC key is pressed, then it will exit from the loop break; printf("You have entered the key : %c\n",ch); } } return 0; }
The output of this code is:
Output:
Enter key ESC to exit You have entered the key : a You have entered the key : B You have entered the key :I You have entered the key : y You have entered the key : 8 You have entered the key : 0 You have entered the key : % You have entered the key : *
This output differs for every person, and it terminates when the user presses the ESC key.
Advantages of kbhit() function in C
The kbhit() function has several advantages while handling keyboard input in C. They are:
- Non-blocking Input: kbhit() offers a non-blocking approach to check for key presses in contrast to conventional input functions, which halt program execution. This makes it possible for the software to carry out other operations while it waits for human input.
- Responsiveness: The kbhit() function enables you to build applications that are responsive and can respond instantaneously to user input. In situations like game development or real-time applications, where prompt user interaction is essential, this is especially helpful.
- User Experience: You can improve your console applications' general user experience by implementing non-blocking keyboard input. Users won't encounter delays or slow response times when using your program.
Although kbhit() is an important function for Windows-based programming, it should be noted that it is not standardized and cannot be available on all platforms or compilers. We might have to use different strategies or libraries that offer comparable functionality while creating cross-platform applications.
Conclusion
The kbhit() function in C provides a practical method for managing keyboard input without delaying program execution. Your console apps can be responsive and engaging, offering a seamless user experience by implementing this feature. kbhit() is a useful tool for Windows-based development even though it is not a standard C function and might not be accessible on all systems. We can create reliable and platform-independent applications by becoming familiar with their usage and looking into alternatives on other platforms.