Common string operations - Cheat Sheet & Quick Revision

Recall & Review

beginner

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

The strlen() function from string.h returns the number of characters in a string, excluding the null terminator.

beginner

How do you copy one string to another in C?

Use the strcpy() function to copy the content of one string into another. Make sure the destination has enough space.

beginner

What does strcmp() do in C?

strcmp() compares two strings and returns 0 if they are equal, a negative value if the first is less, or a positive value if the first is greater.

beginner

How can you concatenate two strings in C?

Use strcat() to append one string to the end of another. The destination string must have enough space to hold the result.

intermediate

Why must you be careful with string operations in C?

Because C strings are arrays of characters ending with a null byte, you must ensure enough memory is allocated to avoid buffer overflows and undefined behavior.

Which function returns the length of a string in C?

A strcpy()

B strlen()

C strcmp()

D strcat()

strlen() counts characters until the null terminator.

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

A The length of the strings

B A negative number

C A positive number

D Zero

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

Which function appends one string to another in C?

A strcat()

B strcpy()

C strlen()

D strcmp()

strcat() adds the second string to the end of the first.

What must you ensure before using strcpy()?

A The destination has enough space

B The strings are the same length

C The source string is empty

D The strings are null-terminated

The destination must have enough space to hold the copied string.

What character marks the end of a string in C?

A Space character

B Newline character

C Null character '\0'

D Tab character

Strings in C end with the null character '\0' to mark their end.

Explain how to safely copy and concatenate strings in C.

Think about destination size and string endings.

Describe what strcmp() returns and how to interpret its result.

Compare two strings alphabetically.