C++ strlen() Function Example | strlen() in C++
C++ strlen() is an inbuilt function that is used to calculate the length of the string. It is a beneficial method to find the length of the string. The strlen() function is defined under the string.h header file.
C++ strlen()
The strlen() takes a null-terminated byte string str as its argument and returns its length. The length does not include a null character. If there is no null character in the string, the behavior of the function is undefined.
Syntax
int strlen(const char *str_var);
Here str_var is the string variable of whose we have to find the length.
Parameter
It takes one parameter which is a pointer that points to the null-terminated byte string. The string is terminated by a null character. If a null character does not terminate it, then the behavior is undefined.
Return Value
It returns an integer giving the length of the passed string.
Example programs on strlen() function
Example 1: Write a program to show the mechanism of the strlen() function.
#include <iostream> #include <string.h> using namespace std; int main() { char k[] = "hello world"; char m[] = "I am the best\n"; char n[] = "a"; char o[] = "123"; int f, i, g, h; f = strlen(k); i = strlen(m); g = strlen(n); h = strlen(o); cout << "String: " << k << endl; cout << "Length: " << strlen(k) << endl; cout << "String: " << m << endl; cout << "Length: " << strlen(m) << endl; cout << "String: " << n << endl; cout << "Length: " << strlen(n) << endl; cout << "String: " << o << endl; cout << "Length: " << strlen(o) << endl; }
Output
String: hello world Length: 11 String: I am the best Length: 14 String: a Length: 1 String: 123 Length: 3
Example 2: Take two input strings and check if the length of both the strings is equal or not using the strlen() function.
See the following code.
#include <iostream> #include <string.h> using namespace std; int main() { char a[] = "Hello I am a geek!"; char b[] = "I love AppDividend!"; if (strlen(a) == strlen(b)) { cout << "Length of both the strings are equal"; } else { cout << "Length of the both the strings are not equal"; } }
Output
Length of both the strings are not equal