wmemcmp() function in C/C++

The wmemcmp() function in C/C++ compare two wide characters. This function compares the first num wide characters of two wide characters pointed by str1 and str2, returns zero if both the strings are equal or different value from zero if they are not.

Syntax:

int wmemcmp (const wchar_t* str1, const wchar_t* str2, size_t num);

Parameters:

• str1: specifies the pointer to the first string.
• str2: specifies the pointer to the second string.
• num: specifies the number of character to be compared.

Return value: This function returns three different values which defines the relationship between two strings:

• Zero: when both strings are equal.
• Positive value: when the first wide character that does not match in both strings has a greater frequency in str1 than in str2.
• Negative value: when first wide character that does not match in both strings has less frequency in str1 than in str2

Below programs illustrate the above function:

Program 1:

// C++ program to illustrate
// wmemcmp() function

#include <bits/stdc++.h>
using namespace std;

int main()
{
    // initialize two strings
    wchar_t str1[] = L"geekforgeeks";
    ;
    wchar_t str2[] = L"geekforgeeks";

    // this function will compare these two strings
    // till 12 characters, if there would have been
    // more than 12 characters, it will compare
    // even more than the length of the strings
    int print = wmemcmp(str1, str2, 12);

    // print if it's equal or not equal( greater or smaller)
    wprintf(L"wmemcmp comparison: %ls\n",
            print ? L"not equal" : L"equal");

    return 0;
}

Output:

wmemcmp comparison: equal

Program 2:

// C++ program to illustrate
// wmemcmp() function
// Comparing two strings with the same type of function
// wcsncmp() and wmemcmp()
#include <bits/stdc++.h>
using namespace std;

int main()
{
    // initialize two strings
    wchar_t str1[] = L"geekforgeeks";
    ;
    wchar_t str2[] = L"geekforgeeks";

    // wcsncmp() function compare characters
    // until the null character is encountered ('\0')
    int first = wcsncmp(str1, str2, 20);

    // but wmemcmp() function compares 20 characters
    // even after encountering null character
    int second = wmemcmp(str1, str2, 20);

    // print if it's equal or not equal( greater or smaller)
    wprintf(L"wcsncmp comparison: %ls\n",
            first ? L"not equal" : L"equal");
    wprintf(L"wmemcmp comparison: %ls\n",
            second ? L"not equal" : L"equal");

    return 0;
}

Output:

wcsncmp comparison: equal
wmemcmp comparison: not equal