String handling using library functions - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is the purpose of the strlen() function in C?

The strlen() function returns the length of a string, not counting the null character \0 at the end.

beginner

How does strcpy() function work in C?

strcpy() copies the content of one string (source) into another string (destination), including the null terminator.

beginner

What does strcmp() return when two strings are equal?

strcmp() returns 0 if the two strings are exactly the same.

intermediate

Explain the difference between strcat() and strncat().

strcat() appends one string to another until it hits the null character. strncat() appends up to a specified number of characters, helping to avoid buffer overflow.

beginner

Why is it important to include string.h when using string library functions?

Including string.h provides the declarations of string handling functions so the compiler knows how to use them correctly.

Which function is used to find the length of a string in C?

A strcpy()

B strcmp()

C strlen()

D strcat()

strlen() returns the number of characters in a string excluding the null terminator.

What does strcpy(dest, src) do?

A Returns length of src

B Compares dest and src strings

C Concatenates src to dest

D Copies src string into dest string

strcpy() copies the source string into the destination string.

If strcmp(s1, s2) returns a negative value, what does it mean?

A s1 is lexicographically less than s2

B s1 is equal to s2

C s1 is lexicographically greater than s2

D There is an error

A negative return means s1 comes before s2 in dictionary order.

Which function safely appends a limited number of characters from one string to another?

A strncat()

B strcpy()

C strlen()

D strcmp()

strncat() appends up to a specified number of characters, preventing buffer overflow.

What header file must be included to use string handling functions like strlen() and strcpy()?

A stdio.h

B string.h

C math.h

D stdlib.h

The string.h header declares all standard string handling functions.

Describe how to copy one string into another using C library functions. What should you be careful about?

Think about how strcpy works and what can go wrong if the destination is too small.

Explain how to compare two strings in C and interpret the result of the comparison.

Consider what strcmp returns when strings are equal or different.