String functions play a key role in manipulating and processing text in C++
And as a C++ programmer, mastering these functions is essential for completing projects and improving your overall programming skills.
In this post, we'll review a comprehensive list of C++ string functions that will help you streamline your string operations and write clean and efficient code.
From searching for a substring to replacing text, this list comes equipped with clear definitions and examples that will help you take your project to the next level.
Without further ado, let's dive in.
C++ String Functions
1. String Length: std::string::length
The string length function calculates the length (number of characters) of a string.
Example:
#include <iostream>
#include <string>
int main() {
std::string str = "Hello, World!";
int length = str.size(); // Returns the length of the string, which is 13
std::cout << "The length of the string is: " << length << std::endl;
return 0;
}
Output:
The length of the string is: 13
2. String Copy: std::strcpy
The string copy function copies a string from a source location to a destination location.
Example:
#include <iostream>
#include <cmath>
int main() {
char source[] = "Hello, World!"; // Source string
char destination[20]; // Destination character array
std::strcpy(destination, source); // Copy the source string to the destination
std::cout << "Source string: " << source << std::endl;
std::cout << "Copied string: " << destination << std::endl;
return 0;
}
Output:
Source string: Hello, World!
Copied string: Hello, World!
3. String Comparison: std::string::compare
The string comparison function compares two strings lexicographically and returns an integer representing the result.
Example:
#include <iostream>
#include <string>
int main() {
std::string str1 = "apple";
std::string str2 = "banana";
int result = str1.compare(str2);
if (result == 0) {
std::cout << "The strings are equal." << std::endl;
} else if (result < 0) {
std::cout << "The string str1 is less than str2." << std::endl;
} else {
std::cout << "The string str1 is greater than str2." << std::endl;
}
return 0;
}
Output:
The string str1 is less than str2.
4. String Conversion to Integer: std::stoi
This function converts a string to an integer.
Example:
#include <iostream>
using namespace std;
int main() {
string str = "123";
int num = stoi(str);
cout << num << endl;
return 0;
}
Output:
123
5. String Conversion to Double: std::stod
This function converts a string to a double.
Example:
#include <iostream>
using namespace std;
int main() {
string str = "3.14";
double num = stod(str);
cout << num << endl;
return 0;
}
Output:
3.14
6. Numeric to String Conversion: std::to_string
This function converts a number to a string.
Example:
#include <iostream>
#include <string>
using namespace std;
int main() {
int num = 42;
string str = to_string(num);
cout << str << endl;
return 0;
}
Output:
42
7. String Concatenation: std::string::operator+
This function concatenates two strings.
Example:
#include <iostream>
#include <string>
using namespace std;
int main() {
string str1 = "Hello";
string str2 = " World!";
string result = str1 + str2;
cout << result << endl;
return 0;
}
Output:
Hello World!
8. String Substring: std::string::substr
The string substring function extracts a substring from a string, starting at a specified position and with a specified length.
Example:
#include <iostream>
#include <string>
int main() {
std::string str = "Hello, World!";
std::string substr = str.substr(7, 5); // Extracts "World" from the original string
std::cout << "The substring is: " << substr << std::endl;
return 0;
}
Output:
The substring is: World
9. String Padding: std::setw
The string padding function pads a string with a specified character or space to a certain width.
Example:
#include <iostream>
#include <string>
using namespace std;
int main() {
string str = "Hello";
cout << setw(10) << setfill(' ') << str << endl;
return 0;
}
Output:
Hello
10. String Replacement:
This function replaces a portion of a string with another string.
Example:
#include <iostream>
#include <string>
using namespace std;
int main() {
string str = "Hello, World!";
str.replace(7, 5, "Universe"); // Replaces the substring "World" with "Universe"
cout << str << endl;=
return 0;
}
Output:
Hello, Universe!
Using String Functions in C++
String functions are a crucial component of any programming language and C++ is no different. Once you're comfortable with these functions, you'll be able to manipulate several lines of text simultaneously to achieve whatever outcome you desire. Keep this post handy as a reference sheet that you can return to whenever you need a quick reminder on how to call string functions in C++.
