C Program — Arrays & Strings
Array
A variable holds a single value, but storing many values one by one quickly gets tedious.
For example, to record three students’ scores:
Declare
DataType arrayName[size] = { values };
Array Input/Output
Two-dimensional Arrays
An array whose elements are themselves arrays.
Declare
DataType arrayName[column][row] = { {values}, {values} };
Two-dimensional Arrays Input/Output
String
Strings
C has no dedicated string type, so a string is represented as a char array:
…or, alternatively, as a pointer:
Declare
char name[size] = {'d', 'a', 't', 'a'};
char name[size] = "data";
Gets/Fgets/Puts
String input / output.
gets doesn’t know the size of the char array — it only stops at a newline or EOF — so it can cause a buffer-overflow security problem.Scanf
String functions
There are many important string functions defined in the string.h library.
Strlen
strlen() returns the length of the given string.
It doesn’t count the null character '\0'.
Strcpy
strcpy(destination, source) copies the source string into destination.
Strcat
strcat(first_string, second_string) concatenates two strings; the result is returned in first_string.
Strcmp
strcmp(first_string, second_string) compares two strings and returns 0 if they are equal.
Strrev
strrev(string) returns the reverse of the given string.
Strlwr
strlwr(string) returns the string in lowercase.
Strupr
strupr(string) returns the string in uppercase.
Strstr
strstr() returns a pointer to the first occurrence of the match string within the given string.
It returns the substring from that first match to the end of the string.
