C Tutorial: An important role of fgets() and fputs()

#include 
#include 
#include 
int main()
{
  char input[10];  // character arrray with index 10
 
  printf("Enter the input: \n");
  gets(input);
  printf("\n\nInput is: \n");
  puts(input);
  getch();
  return 0;
}
 

In this program, I've used gets() to take the input. Many of you might've noticed that, even though the index is just 10, we are able to input as many characters as possible whereas the program was supposed to take 9 characters + 1 string terminator (NULL character). This happens because, there is a lot of free space available in the buffer, hence, the program uses that space to take up the input, But, after some extent the buffer gets OVERLOADED and hence it doesn't produce the desired output. Instead, the program shows a error message and gets closed automatically. This is the major drawback of this program, as user doesn't know the size of character array being used and they may enter more characters than required.​

example:
Input for the program...

​

​

Error after execution....​

​

​

​

So, to overcome this problem, fgets() and fputs() play an important role. The only difference between the gets() and fgets() is the syntax. To get the input from the keyboard using fgets() the following syntax is followed.

fgets(input, sizeof(input), stdin);

Similarly, for fputs(),

fputs(input, sizeof(input), stdout);

so, the above code snippet can now be written as,

​

#include 
#include 
#include 
int main()
{
  char input[10];  // character arrray with index 10
 
  printf("Enter the input: \n");
  fgets(input, sizeof(input), stdin);    // stdin is buffer input
  printf("size of input is %d", sizeof(input))
  printf("\n\nInput is: \n");
  fputs(input, sizeof(input), stdout);    // stdout is buffer output
  getch();
  return 0;
}