What does strcmp() function return?
When the strings are not equal, the value returned by the strncmp() function is the difference between the ASCII values of the first unmatched character in str1 and str2.
The strncmp() function returns three different types of integer values on the basis of comparison.
1. Greater than zero ( >0 )
A positive value is returned if a character of str1 and str2 doesn’t match before the num characters and the ASCII value of the str1 character is greater than the ASCII value of the str2 character. As a result, we can say that str1 is lexicographically greater than str2.
Example
C++
// C, C++ program to demonstrate// functionality of strncmp()#include <cstring>#include <iostream>using namespace std;int main(){ // Take any two strings char str1[10] = "akash"; char str2[10] = "akas"; // Compare strings using strncmp() int result = strncmp(str1, str2, 4); if (result == 0) { // num is the 3rd parameter of strncmp() function cout << "str1 is equal to str2 up to num characters" << endl; } else if (result > 0) cout << "str1 is greater than str2" << endl; else cout << "str2 is greater than str1" << endl; cout << "Value returned by strncmp() is: " << result << endl; return 0;} |
str1 is greater than str2 Value returned by strncmp() is: 18
2. Less than zero ( <0 )
A negative value is returned, if a character of str1 and str2 doesn’t match before the num characters and the ASCII value of the str1 character is lesser than the ASCII value of the str2 character. As a result, we can say that str2 is lexicographically greater than str1.
Example
C++
str2 is greater than str1 Value returned by strncmp() is: -18
3. Equal to zero ( 0 )
This function returns zero if the characters of str1 match with the characters of the str2 up to num characters. As a result, we cannot say that str1 is equal to str2 until num is equal to the length of either string.
Example
C++
// C, C++ program to demonstrate// functionality of strncmp()#include <cstring>#include <iostream>using namespace std;int main(){ // Take any two strings char str1[10] = "akash"; char str2[10] = "akas"; // Compare strings using strncmp() int result = strncmp(str1, str2, 4); if (result == 0) { // num is the 3rd parameter of strncmp() function cout << "str1 is equal to str2 up to num characters" << endl; } else if (result > 0) cout << "str1 is greater than str2" << endl; else cout << "str2 is greater than str1" << endl; cout << "Value returned by strncmp() is: " << result << endl; return 0;} |
str1 is equal to str2 upto num characters Value returned by strncmp() is: 0
std::strncmp() in C++
std::strncmp() function in C++ lexicographically compares not more than count characters from the two null-terminated strings and returns an integer based on the outcome. This function is a Standard Library function that is defined in <cstring> header file in C++.
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