In-depth discussion on strcmp string comparison using C ++

Implementation of strcmp
Function introduction prototype: extern int strcmp (const char * s1, const char * s2 );
Usage:Add the header file # include <string. h>
Function:Compares s1 and s2 strings.
General format:Strcmp (string 1, string 2)
Return Value:
When s1 <s2, return value <0
When s1 = s2, the return value is 0.
When s1> s2, return value> 0
That is, two strings are compared from left to right one by one (compare by ASCII value) until different characters or '\ 0' appear. For example: "A" <"B" a ">" A "" computer ">" compare"
Note:
1. strcmp (const char * s1, const char * s2) can only compare strings, numbers, and other parameters.
2. For the return value, the standard only specifies three values: Less Than Zero, zero, and greater than zero. The compiler determines the specific value. Therefore, when programming, it cannot determine whether the value is greater than or equal to 1 or-1, for example, strcmp ("123", "1234") in VC ") -1 is returned, and-52 is returned in TC.

The following is my own implementation. I hope to correct it! (Here I return-1, 0, 1)Copy codeThe Code is as follows: # include "stdafx. h"
# Include <iostream>
# Include <assert. h>
Using namespace std;
<P> int mystrcmp (const char * str1, const char * str2)
{
Assert (str1! = NULL & str2! = NULL); </P> <P> while (* str1 & * str2 & * str1 = * str2)
{
++ Str1;
++ Str2;
}
If (* str1> * str2)
Return 1;
If (* str1 <* str2)
Return-1;
Else
Return 0;
} </P> int _ tmain (int argc, _ TCHAR * argv [])
{
Char * str1 = "Hello World ";
Char * str2 = "Hello world ";
Cout <mystrcmp (str1, str2) <endl;
Return 0;
}