c语言 strcmp函数_了解C ++ strcmp（）函数

c语言 strcmp函数

Hello, folks! In this article, we will be focusing on the working of the C++ strcmp function in detail.

大家好！在本文中，我们将重点关注C ++ strcmp函数的详细工作。

C ++ strcmp（）函数入门 (Getting started with C++ strcmp() function)

C++ strcmp() function is an efficient way to compare two strings lexiographically.

C ++的strcmp（）函数是比较两个串的有效方式lexiographically 。

The strcmp() function compares two input strings in a lexicographic manner and returns an integer value based on the outcome of the comparison of the two input strings.

strcmp()函数以字典方式比较两个输入字符串，并根据两个输入字符串的比较结果返回一个整数值。

By lexicographic comparison, we mean, that two strings are actually compared with their ASCII values of every character. If found same, zero is returned and the string is said to be equal.

通过词典比较，我们的意思是， 实际上将两个字符串与每个字符的ASCII值进行比较 。如果发现相同，则返回零，并说该字符串相等。

Syntax:

句法：


strcmp(string1,string2)

Example:

例：


#include<stdio.h>
#include<string.h> int main()
{  char str1[] = "Python"; char str2[] = "Python"; if(strcmp(str1, str2)==0)printf("Strings are equal");elseprintf("\nThe strings are not equal");return 0;
}

Output:

输出：


Strings are equal

strcmp（）函数返回的值 (Value returned by the strcmp() function)

The strcmp() compares the strings lexicographically and returns either of the following values based on the comparison:

strcmp（）按字典顺序比较字符串，并根据比较结果返回以下两个值之一：

value = zero(0): The function returns 0, if both the strings are lexicographically equal i.e. both the strings are identical.value = zero(0) ：如果两个字符串在字典上相等，即两个字符串相同，则该函数返回0。
value > zero(0): It returns a value greater than zero, if the first non-matching character of the string1 has a greater ASCII value than the character present in the string2.value > zero(0) ：如果string1的第一个不匹配字符的ASCII值大于string2中出现的字符，则返回大于零的值。
value < zero(0): It returns a value less than zero, if the first non-matching character of the string1 has less ASCII value than the character present in the string2.value < zero(0) ：如果string1的第一个不匹配字符的ASCII值小于string2中出现的字符，则返回小于零的值。

变体1：strcmp（）函数返回零（0） (Variant 1: The strcmp() function returns zero(0))

The strcmp() function returns zero if both the strings are identical.

如果两个字符串相同，则strcmp（）函数将返回零。

Example:

例：


#include<stdio.h>
#include<string.h> int main()
{  char str1[] = "Python"; char str2[] = "Python"; int val_strcmp=0;val_strcmp = strcmp(str1, str2);printf("The return value of strcmp() function: %d" , val_strcmp); return 0;
}

Output:

输出：


The return value of strcmp() function: 0

形式2：strcmp（）函数返回的值“大于零” (Variant 2: The strcmp() function returns a value ‘greater than zero’)

A value greater than zero is returned if the ASCII value of the first non-matching character of string1 is found to be greater than the ASCII value of the corresponding character of string2.

如果发现string1的第一个不匹配字符的ASCII值大于string2的相应字符的ASCII值，则返回大于零的值。

Lets’s take an example:

让我们举个例子：

string1 = ‘yz’

string1 ='yz'

string2 = ‘ab’

string2 ='ab'


strcmp(string1,string2)

When two strings are not identical, the function returns the difference between the ASCII values of the first non-matching characters of the two strings.

当两个字符串不相同时，该函数将返回两个字符串的第一个不匹配字符的ASCII值之间的差。

In the above example, the function returns 24 because ASCII value of ‘y’ – ASCII value of ‘a’ is 24

在上面的示例中，该函数返回24，因为ASCII值“ y”-ASCII值“ a”为24

i.e 121 – 97 = 24

即121 – 97 = 24

Example:

例：


#include<stdio.h>
#include<string.h> int main()
{  char str1[] = "wxyz"; char str2[] = "abcd"; int val_strcmp=0;val_strcmp = strcmp(str1, str2);printf("The return value of strcmp() function: %d" , val_strcmp); return 0;
}

In the above snippet of code, the ASCII value of ‘w’ – ASCII value of ‘a’ is more than zero i.e. 119 – 97 = 22

在上面的代码片段中，“ w”的ASCII值–“ a”的ASCII值大于零，即119 – 97 = 22

Output:

输出：


The return value of strcmp() function: 22

变体3：strcmp（）函数返回的值小于零 (Variant 3: The strcmp() function returns a value ‘less than zero’)

The strcmp() function returns a value less than zero, if the ASCII value of the first non-matching character of the first string is less than the ASCII value of that particular character of the second string.

如果第一个字符串的第一个不匹配字符的ASCII值小于第二个字符串的那个特定字符的ASCII值，则strcmp（）函数返回小于零的值。

Consider the strings, string1 = ‘ab’ and string2 =’yz’

考虑字符串string1 ='ab'和string2 ='yz'

The ASCII value of ‘a’ is less than ASCII value of ‘y’ i.e. 97 – 121 = -24.

ASCII值“ a”小于ASCII值“ y”，即97 – 121 = -24。

Thus, the value returned by the function is less than zero i.e. -24.

因此，函数返回的值小于零，即-24。

Example:

例：


#include<stdio.h>
#include<string.h> int main()
{  char str1[] = "ab"; char str2[] = "yz"; int val_strcmp=0;val_strcmp = strcmp(str1, str2);printf("The return value of strcmp() function: %d" , val_strcmp); return 0;
}

Output:

输出：


The return value of strcmp() function: -24

C ++ strcmp（）方法一目了然！ (C++ strcmp() method at a glance!)

The strcmp() function compares the characters of the strings in a lexicographic manner.strcmp（）函数以字典方式比较字符串的字符。
Moreover, the function returns an integer based on the comparison.此外，该函数根据比较结果返回一个整数。
An integer value greater than zero is returned if the ASCII value of the first non-matching character of the first string is greater than the second one.如果第一个字符串的第一个不匹配字符的ASCII值大于第二个，则返回大于零的整数值。
If the strings are identical, the function returns zero.如果字符串相同，则函数返回零。
A value less than zero is returned by the function if the ASCII value of the first non-matching character of the first string is less than the second one如果第一个字符串的第一个不匹配字符的ASCII值小于第二个，则函数返回小于零的值

结论 (Conclusion)

Thus, in this article, we have understood the working of strcmp() function in C++.

因此，在本文中，我们了解了C ++中strcmp（）函数的工作方式。

参考资料 (References)

String comparison — JournalDev字符串比较— JournalDev

翻译自: https://www.journaldev.com/38264/c-plus-plus-strcmp-function

c语言 strcmp函数