A string is nothing but an one dimensional array of char. String literal are words surrounded by double quotation marks .
| “Welcome to gyantoday” |
In C every string is terminated by a null character ‘\0’ see an example below.
char str[20];
str is a 20 element character array, we can store up to 19 character in this array, because last character must be a null character.
Initializing array of type char
| char str[10] = “gyantoday” ;In above char array str[9] is ‘\0’ null character, sizeof(str) is 10 and length of str is 9.Lets see one more example.
char str1[] = “gyan” /* Here sizeof(str1) is 5, but length of str1 is 4 */ |
There are number of library functions for string handling and manipulation. These all libraray functions defined in <string.h> header file. Some of the frequently used string handling library functions given below.
| String handling Library functions | Purpose of function |
| strlen() | Find length of a string |
| strcpy() | Copies a string into another |
| strncpy() | Copies first n character of a string at the end of another string |
| strcmp() | Compare two strings |
| strncmp() | Compare first n character of two strings |
| strcat() | Appends one string at the end of another string |
| strncat() | Appends first n character of string at the end of another string |
| strset() | Set all character of string to a given character |
| strrev() | Reverse a string |
| strupr() | Converts a string to upper case |
| strlwr() | Converts a string to lower case |
| strcasecmp() | Compare two strings case insensitive |
| strncasecmp() | Compare first n character of two strings case insensitive |
An example program of string handling.
| #include<stdio.h>#include<string.h>int main(){
char str[50]; int length; printf(“Enter any string\n”); gets(str); length = strlen(str); printf(“String length = %d\n”,length); printf(“Print given string\n”); puts(str); return 0; } Suppose input string is “Welcome to gyantoday” then output will be “Welcome to gyantoday”
Output: Enter any string Welcome to gyantoday String length = 20 Print given string Welcome to gyantoday |
Write your own program of strlen()
Write your own program of strcpy()