Strcmp function in C++
An integrated utility function, strcmp(), has been defined in the header file "string.h." The string parameters are compared using this method. By comparing the two strings' letter by personality, it analyzes them lexicographically. The comparison begins with the first byte of each string until either the characters used in both strings are the same or an empty character is encountered.
It verifies the following letter and if the initial character in both strings is the same. This procedure will be carried out repeatedly until a NULL letter turns up or the two protagonists are uneven.
To compare two null-terminated strings in C++, utilize the strcmp method. The header file (or C) contains its declaration. When the function runs, an integer represents the connection between the strings.
The signature of the strcmp function is as follows:
#include <cstring>
int strcmp(const char* str1, const char* str2);
- Here, the strings that need to be checked are str1 and str2.
- The method gives a negative value if str1 is lexicographically smaller than str2.
- In case str1 exceeds str2 lexicographically, this function yields a positive value.
- The function returns zero if the two characters are equal.
Example Code:
#include <iostream>
#include <cstring>
int main() {
const char* stra = "potato";
const char* strb = "tomato";
int result = strcmp(stra, strb);
if (result < 0) {
std::cout << "stra is less than strb\n";
} else if (result > 0) {
std::cout << "stra is greater than strb\n";
} else {
std::cout << "stra is equal to strb\n";
}
return 0;
}
Output:
![Strcmp function in C++](https://static.tutorialandexample.com/cpp/strcmp-function-in-cpp1.png)
This example shows how to use strcmp to compare the characters "apple" and "banana" and print the outcome depending on the string's lexicographical order. Remember that strcmp evaluates characters according to their ASCII values and is case-sensitive. Use stricmp (Windows) or strcasecmp (Unix-like platforms) if you require a case-insensitive contrast, but keep in mind that these methods are not included in the C++ standards and may not be accessible on all systems. An alternative is to use strcmp after converting the characters into lowercase (or uppercase).
Important details regarding the C++ strcmp function:
- Header File Being Included: The <cstring> headers file contains the declaration of the strcmp function.
- Function Signature: The following is the function's definition for strcmp:
constant char* str1, const char* str2; int strcmp;
- Return Quantities: A negative numerical value is returned if stra is lexicographically smaller than strb.
- An integer bigger than zero if stra is lexicographically larger than strb.
- It returns 0 if the two characters are equivalent.
- The strcmp function is case-sensitive. Letters in uppercase and lowercase are regarded differently.
- Comparison Logic: Until a distinction is discovered or one of the strings is reached, it analyzes the string character by character.
- The alternative in C++, Std::string, which offers greater capability and tends to be safer than C-style characters, is frequently used for string processing in current C++.
Benefits of implementing strcmp:
- Easy to Utilize: Comparing two strings doesn't require you to diligently examine every letter and compare it separately; instead, the strcmp function offers a straightforward solution.
- It is widely accessible and maintained on various systems because it is a component of the C standards library. Code written with strcmp can now run on various platforms.
- Efficiency: Optimization of performance is frequently applied when implementing strcmp. It is space- and time-efficient and can benefit from low-level enhancements.
- A simple Explanation of the Connection Among Two Strings is Made Possible by the Function's Numeric Return Value. Because of this, program logic can be used for circumstances and splitting.
- Lexicographical Comparisons: For many uses where string ordering is important, strcmp's lexicographical (dictionary) comparing function is useful.
- Interoperability with C-style Strings: strcmp is an obvious choice if you work with letter arrays or C-style strings. It is immediately compatible with null-terminated strings, which are a standard C representation.
Restrictions and possible drawbacks:
- Type Security Vulnerability: The strcmp function works with C-style characters, effectively character arrays. It lacks the type safety and adaptability of std::string in C++. If not used carefully, using C-style strings might result in buffer overflows and other memory-related problems.
- The purpose of strcmp is to compare null-terminated text arrays; it is inappropriate for binary data. Strcmp is not the right option if you need to contrast binary information or strings that may contain null characters.
- Dependency on Null Termination: The null-termination hypothesis is the foundation of strcmp. A missing null character may cause undefinable behaviour or inaccurate outcomes. It may be prone to errors because of its dependence on null terminating.
- The stringcmp function is case-sensitive. If a type-insensitive comparison is necessary, more features or modifications might be needed, or one could think about changing the character's case before employing strcmp.
- Restricted Comparing Information: Only the equality of the lexicographically larger or smaller string is indicated by the returned value of strcmp. It can be restrictive in some situations because it doesn't offer details about the actual distinctions between the strings.