A string is an array of characters. The end of the string is marked with a special character, the null character, which is simply represented by '\0'. Strings are enclosed by double quotes whereas, character is enclosed by single quotes always.
Declaration :
Strings are array of char data type. It is declared as follow :
char s[5] ;
Initialization :
char message [20] = "Hello world !";
char message [20] = {'H', 'e', 'l', 'l', 'o', '\0'};
char message [] = "Hello!"
when we declare "char message[20]”, 20 bytes of memory space is allocated for the string value. And when we declare "char message[]”, memory space will be allocated as per the requirement during execution time of program.
Example1 :
#include<stdio.h>
int main()
{
char message[10] = "Hello!";
char message1[] = " world" ;
printf("%s, %s, message, message1);
return 0;
}
Output :
Hello! world
Example2:
#include<stdio.h>
int main()
{
char value[];
printf("Enter any string : ");
scanf("%s",&value);
printf("Entered String = %s ", value);
return 0;
}
Output :
Enter any string :
GoProgramming
Entered String = GoProgramming
scanf() function doesn't control the value with space. For this we use gets() instead of scanf().
gets(variable);
Example3:
#include<stdio.h>
int main()
{
char value[];
printf("Enter any string : ");
gets(value);
printf("Entered String = %s ", value);
return 0;
}
Output :
Enter any string :
Go Programming
Entered String = Go Programming
String Handling Functions :
Sometimes, we need to manipulate string in our program according to our needs. For this C programming language provide us some in-built String Manipulation Functions which are available in <string.h> header file.
These functions are listed below :
- strlen() :
strlen() function is used to count the number of characters in a string.
Example :
#include<stdio.h>
#include<string.h>
int main()
{
char value[] = "Hello World";
int length;
length = strlen(value);
printf("String length = %d", length);
return 0;
}
Output :
String length = 11
- strrev()
It reverses the given string.
Example :
#include<stdio.h>
#include<string.h>
int main()
{
char value[] = "Hello";
char value1[];
length = strrev(value);
printf("String = %s", value);
printf("Reversed String = %s, value1);
return 0;
}
Output :
String = Hello World
Reversed String = olleH
- strcpy()
This function copies a string value into another string.Example :
#include<stdio.h>
#include<string.h>
int main()
{
char value[] = "Hello";
char value1[] = "World";
char value2[];
strcpy(value2, value);
strcpy(value2, value1);
printf("String 1 = %s", value);
printf("String 2 = %s", value1);
printf("New String = %s", value2);
return 0;}
Output :
String 1 = Hello
String 2 = World
New String = HelloWorld
- strcmp() :
strcmp() function is used to compare two strings. If both strings are equal then function will return value zero(0). If first string is greater than second than function return value >0 otherwise <0. This function is case sensitive.
Example :
#include <stdio.h>
#include <string.h>
int main()
{
char str1[] = "abcd",
str2[] = "abCd",
int result;
// comparing strings str1 and str2
result = strcmp(str1, str2);
if(result < 0)
{
printf("str1 is less than str2");
}
else if(result > 0)
{
printf("str2 is less than str1");
}
else
{
printf("str1 is equal to str2");
}
return 0;
}
Output :
str2 is less than str1
strcat()
This function is used to concatenate two or more strings.
Syntax :
strcat(str1, str2);
strcat(str1, strcat(str2,str3));
