C++

C++ String Functions

---

As you have learned in chapter 13, strlen, strcat, strcmp are all string functions of C++. Two similar string functions are the strncat, and strncmp. These work the same as strcat, and strcmp except they allow more control over how the function operates. Strncat allow the programmer to specify the number of characters of the source string that will be appended onto the destination string. It is used as follows:

strncat(destination, source, number of characters);

Example:

char FirstName[15] = "John ";

char LastName[15] = "Smith";

strncat(FirstName, LastName, 1);

count << Firstname;

Output:

        John S

The strncmp, and strnicmp allow the comparison of only the first number of specified characters to be compared. The only difference between the two is strnicmp is not case sensitive. It is used as follows:

strncmp(string1, string2, number of characters);

Example:

char FirstName1[15] = "Rob";

char FirstName2[15] = "Robert";

test = strncmp(FirstName, LastName, 3);

cout << test;

Output:

0

Many more string functions are available in C++. Some of these functions and examples of each are shown below. You should review your compiler's documentation before using these functions in order to avoid unexpected results.

_strlwr

Converts all characters to lower case.

_strlwr(string);

_strupr

Converts all characters to upper case.

_strupr(string);

strrev

Reverses the string.

strrev(string);

strchr

Locates the first occurrence of a character in a string.

CharPointer = strchr(string, 'char');

strrchr

Locates the last occurrence of a character in a string.

CharPointer = strrchr(string, 'char');

strspn

Returns the number of matches found in the string.

Count = strspn(string, 'char');

strpbrk

Returns a character pointer to the first occurrence of characters in a string. It will return the pointer of which ever character comes first.

CharPointer = strpbrk(string, "chars")

strstr

Returns a character pointer to the first occurrence of a string in a string.

CharPointer = strstr(string, "string");