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std::memcmp() in C++

  • Difficulty Level : Easy
  • Last Updated : 06 Oct, 2017

It compares the first count characters of the arrays pointed to by buf1 and buf2.
Syntax:

int memcmp(const void *buf1, const void *buf2, size_t count);
Return Value: it returns an integer.
Parameters:  
buf1 : Pointer to block of memory.
buf2 : Pointer to block of memory.
count : Maximum numbers of bytes to compare.
Return Value is interpreted as :
Value                                Meaning
Less than zero                       buf1 is less than buf2.
Zero                                 buf1 is equal to buf2.
Greater than zero                    buf1 is greater than buf2.

Example 1. When count Greater than zero( > 0)




// CPP program to illustrate std::memcmp()
#include <iostream>
#include <cstring>
  
int main()
{
    char buff1[] = "Welcome to GeeksforGeeks";
    char buff2[] = "Hello Geeks ";
  
    int a;
  
    a = std::memcmp(buff1, buff2, sizeof(buff1));
  
    if (a > 0)
        std::cout << buff1 << " is greater than " << buff2;
    else if (a < 0)
        std::cout << buff1 << "is less than " << buff2;
    else
        std::cout << buff1 << " is the same as " << buff2;
  
    return 0;
}

Output:

Welcome to GeeksforGeeks is greater than Hello Geeks 

Example 2. When count less than zero( < 0)




// CPP program to illustrate std::memcmp() 
#include <cstring>
#include <iostream>
  
int main()
{
    int comp = memcmp("GEEKSFORGEEKS", "geeksforgeeks", 6);
    if (comp == 0) {
        std::cout << "both are equal";
    }
    if (comp < 0) {
        std::cout << "String 1  is less than String 2";
    } else {
        std::cout << "String 1 is  greater than String 2";
    }
}

Output:



String 1 is less than String 2

Example 3 : When count equal to zero ( = 0)




// CPP program to illustrate std::memcmp()
#include <iostream>
#include <cstring>
  
int main()
{
    char buff1[] = "Welcome to GeeksforGeeks";
    char buff2[] = "Welcome to GeeksforGeeks";
  
    int a;
  
    a = std::memcmp(buff1, buff2, sizeof(buff1));
  
    if (a > 0)
        std::cout << buff1 << " is greater than " << buff2;
    else if (a < 0)
        std::cout << buff1 << "is less than " << buff2;
    else
        std::cout << buff1 << " is the same as " << buff2;
  
    return 0;
}

Output:

Welcome to GeeksforGeeks is the same as Welcome to GeeksforGeeks

This article is contributed by Shivani Ghughtyal. If you like GeeksforGeeks and would like to contribute, you can also write an article using contribute.geeksforgeeks.org or mail your article to contribute@geeksforgeeks.org. See your article appearing on the GeeksforGeeks main page and help other Geeks.

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