Discussion: Hello, stdin
Explore how the setbuf function manages output buffering in C, controlling when text appears during program execution. Understand the differences between unbuffered, block buffered, and line buffered modes. Learn why pressing Enter flushes the output buffer and how buffering affects standard input and output behavior in stream I/O. This lesson helps you grasp essential concepts for managing interactive and non-interactive I/O in C programming.
We'll cover the following...
Run the code
Now, it's time to execute the code and observe the output. After you press the "Run" button, press "Enter" to see the output.
#include <stdio.h>
int main()
{
char buffer[BUFSIZ]; /* BUFSIZ is a constant defined in stdio.h */
setbuf(stdout, buffer);
puts("Wait for it!");
puts("Wait for it!");
puts("Now!");
getchar();
puts("Whew!");
return(0);
}Understanding the output
No output is generated when the program starts. Press the "Enter" key, and the following text appears:
Wait for it!Wait for it!Now!Whew!
We won’t understand the output order unless we know what the setbuf() function does. Even if you don’t, look at the presentation:
setbuf(stdout, buffer);
The first argument is the stdout constant, representing the standard output device. The second argument is the character array buffer. As the ...