C-string
The
C language uses the term string to
refer to null-terminated char arrays. In the C language they
are
used to store character data. In C++ we have the string class.
For
example, consider the literal constant string, "HELLO"
It
occupies 6 bytes of memory. Its type is const char*
Memory
"looks" like this:
What
is a null-terminated char array?
To
assign this literal constant to a variable ...
char array[6];
strcpy(array,"hello");
// copies the literal into the memory location, array
// array =
"hello";
// ERROR!!! This will not work. Why not?
Example 2-6 and 2-7 from Joe's Notes on Dynamic Memory Allocation
C-string functions
The
C-string functions operate on C-strings (aka null
terminated char array).
These
functions require the
<cstring> header file.
| Function |
Prototype |
Description |
| strcpy |
char* strcpy(char* destination, const char*
source); |
Copies from the source string to the destination
string |
| strncpy |
char* strncpy(char* destination, const char*
source, size_t n); |
Copies n bytes from the source string to the
destination string |
| strcat |
char* strcat(char* destination, const char*
source); |
Appends the source to the end of the destination |
| strncat |
char* strncat(char* destination, const char*
source, size_t n); |
Appends n bytes from the source to the end of the
destination |
| strcmp |
int strcmp(const char* s1, const char* s2); |
Compares s1 and s2.
Returns 0 if equal, negative int if s1 < s2, positive int if s1
> s2 |
| strncmp |
int strncmp(const char* s1, const char* s2,
size_t n); |
Compares n bytes of s1 and s2. |
| strstr |
const char* strstr(const char* s1, const char*
s2);
char* strstr(char* s1, const char* s2); |
Searches string s1 for string s2 |
| strchr |
const char* strchr(const char* str, int ch);
char* strchr(char* str, int ch); |
Searches string for a character |
| strrchr |
const char* strrchr(const char* str, int ch);
char* strrchr(char* str, int ch); |
Searches string for a character starting at the
end of the string |
| strlen |
size_t strlen(const char* str); |
Returns the length of the string |
| strtok |
char* strtok(char* str, const char* delimiterset); |
Parses string str using any character contained
in delimiterset |
Example
For
the file shown below, print the results shown below. Use only
<cstring> or <cctype> functions for the
parsing.
Input File
Cincinnati
27, Buffalo 24
Detroit
31, Cleveland 17
Kansas
City 24, Oakland 7
Carolina
35, Minnesota 10
Pittsburgh
19, NY Jets 6
Philadelphia
31, Tampa Bay 20
Green
Bay 19, Baltimore 17
St.
Louis 38, Houston 13
Denver
35, Jacksonville 19
Seattle
20, Tennessee 13
New
England 30, New Orleans 27
San
Francisco 32, Arizona 20
Dallas
31, Washington 16
|
Output
File
Cincinnati over Buffalo 27 to 24
Detroit over Cleveland 31 to 17
Kansas City over Oakland 24 to 7
Carolina over Minnesota 35 to 10
Pittsburgh over NY Jets 19 to 6
Philadelphia over Tampa Bay 31 to 20
Green Bay over Baltimore 19 to 17
St. Louis over Houston 38 to 13
Denver over Jacksonville 35 to 19
Seattle over Tennessee 20 to 13
New England over New Orleans 30 to 27
San Francisco over Arizona 32 to 20
Dallas over Washington 31 to 16 |
Character Type Functions
|