What is the default return-type of getchar()?a.charb.Intc.char *d.reading character doesn’t require a return-type

The getchar() function is a standard input function in C that reads the next character from the standard input (stdin) and returns it. Here's a detailed breakdown of the options given:

1. Option a: char - This option suggests that the return type of getchar() is a character type. This is true as getchar() returns the next character input as an int, which can represent any valid character or an EOF (end-of-file) condition.

2. Option b: int - This option indicates that the return type is an integer. This is also correct because while getchar() reads a character, it returns it as an int, allowing for error checking against EOF.

3. **Option c: char *** - This option suggests that the return type is a pointer to a character array (string). This is incorrect because getchar() does not return a string or a character array.

4. Option d: reading character doesn’t require a return-type - This option is misleading since any function in C must specify a return type, and getchar indeed returns a value.

Conclusion

The most accurate answer regarding the default return type of getchar() is b. int, since it returns the next character as an int for proper handling of both valid characters and EOF.