String Operations in C++ can be used to make the work easier by using the functions in short form of commands. And we are having different types of operations in strings. They have been listed as follows:
| String Operation | Functions | Description |
|---|---|---|
| Concatenation | addition operator | It is used for concatenating strings together |
| Formatting Data | reads | It can read values from strings into IDL variables |
| Case Folding | strlowcase, strupcase | converts its arguments into upper case and lower case |
| White Space Removal | STRCOMPRESS, STRTRIM | Used to eliminate unwanted whitespaces from the string arguments. |
| Length | STRLEN | used for finding the length |
| Substrings | STRPOS, STRPUT, STRMID | used for inserting, locate, and extract strings from their substrings |
| Splitting and Joining strings | STRSPLIT, STRJOIN | Used to break the strings and also glues string together |
| Comparing strings | STRCMP, STRMATCH, STREGEX | It performs string comparisons |
Concatenation of Strings in C++
The Concatenation of strings in C++ helps us to join the two strings by using the ‘+’ addition operator.
Example:
string s1 = "Have a"; string s2 = "nice day"; string s3 = s1 + s2; cout << s3 << endl;
Output:
Have a nice day
Formatting Data of strings in C++
The formatting data of strings in C++ will be having using function reads to format the data on strings. The READS procedure performs formatted input from a string variable and writes the results into one or more output variables.
It is useful when you need to examine the format of a data file before reading the information it contains. And each line of the file can be read into a string using READF. While the components of that line can be read into variables using READS.
Syntax: READS, Input, Var1, …, Varn
Case Folding in C++ | toupper, tolower
The case folding in C++ can be defined as a process applied to a sequence of characters in which those identified as a non-upper case to upper case.
Example:
#include<bits/stdc++.h>
using namespace std;
int main()
{
//su is the string which is converted to uppercase
string su = "Andhra Pradesh";
//using transform() function and ::toupper in STL
transform(su.begin(), su.end(), su.begin(), ::toupper);
cout << su << endl;
//sl is the string which is converted to lowercase
string sl = "Andhra Pradesh";
//using transform() function and ::tolower in STL
transform(sl.begin(), sl.end(), sl.begin(), ::tolower);
cout << sl << endl;
return 0;
}
Output:
ANDHRA PRADESH
andhra pradesh
White Space Removal in C++ | STRCOMPRESS( String, /REMOVE_ALL )
The white space removal in C++ uses compress( ) and trim( ) methods for removing unwanted spaces.
Syntax: Result = STRCOMPRESS( String, /REMOVE_ALL )
Example:
str = " I D L is C o o l ! " PRINT, str.Strlen( ) newstr = str.Compress() ; Print the new string and its length. PRINT, newstr, newstr.Strlen( )
Output:
20
IDLisCool!
10
Length of String in C++ | strlen(string)
The strlen( ) is used for getting the length of the string.
Syntax: strlen(string)
Example:
#include<stdio.h>
#include <string.h>
int main()
{
char ch[]={'f', 'r', 'e', 's', 'h','e','r','s','n','o','w','\0'};
printf("Length of string is: %d", strlen(ch));
return 0;
}
Output:
Length of string is: 11
Example 2
#include<stdio.h>
#include<string.h>
int main()
{
char str[]= "freshers";
printf("Length of string is: %d", strlen(str));
return 0;
}
Output:
Length of string is: 8
Example 3
#include<stdio.h>
#include <string.h>
int main()
{
char *str = "freshersnow";
printf("Length of string is: %d", strlen(str));
return 0;
}
Output:
Length of string is: 11
SubStrings in C++
The Substrings in C++ function takes two values pos and len as an argument and returns a newly constructed String object with its value initialized to a copy of a substring of this object. If pos is equal to the string length, the function returns an empty string. In case if pos is greater than the string length, it throws out_of_range. If this happens, there are no changes in the string.
Syntax:
string substr (size_t pos, size_t len) const;
Parameters:
pos: Position of the first character to be copied.
len: Length of the sub-string.
size_t: It is an unsigned integral type.
Return value: It returns a string object.
Example:
#include <string.h>
#include <iostream>
using namespace std;
int main()
{
//Take any string
string s1 = "Freshers";
//Copy three characters of s1 (starting from position 1)
string r = s1.substr(1, 3);
//prints the result
cout<<"String is: " << r;
return 0;
}
Output:
String is: res
Splitting and Joining Strings in C++
The splitting and joining of strings in C++ have split( ) and join( ) methods for using.
STRSPLIT()
The STRSPLIT function splits its input String argument into separate substrings, according to the specified delimiter or regular expression. And by default, the position of the substrings is returned. While the EXTRACT keyword can be used to cause STRSPLIT to return an array containing the substrings.
Comparing Strings in C++
The comparison of strings in C++ can be done in two ways. They are as follows:
Example:
#include <iostream>
using namespace std;
void relationalOperation(string s1, string s2)
{
if(s1 != s2)
cout<< s1 << "is not equal to "<<s2 << endl;
if (s1 > s2)
cout<< s1 <<"is greater than "<< s2 << endl;
else
cout<<s2 <<"is greater than"<< s1 << endl;
}
//Main function
int main()
{
string s1("Freshers");
string s2("freshersnow");
relationalOperation(s1, s2);
return 0;
}
Output:
Freshers is not equal to freshersnow
freshersnow is greater than Freshers
Example: compare( )
#include<iostream>
using namespace std;
void compareFunction(string s1, string s2)
{
//comparing both using inbuilt function
int x = s1.compare(s2);
if (x != 0)
cout<< s1 <<"is not equal to "<<s2 << endl;
if (x > 0)
cout<< s1 <<"is greater than"<<s2 << endl;
else
cout<< s2 <<"is greater than "<<s1 << endl;
}
//Main function
int main()
{
string s1("Freshers");
string s2("freshersnow");
compareFunction(s1, s2);
return 0;
}
Output:
Freshers is not equal to freshersnow
freshersnow is greater than Freshers