String compare in c

Let's look at some of the operations that can be performed on a C string without modifying the string s involved. When the strings passed to strcmp contains exactly same characters in every index and have exactly same length, it returns 0.

For example, i will be 0 in the following code:. If the passed parameters aren't same, strcmp returns either a positive or a negative integer. For example:. This is the first character index 8 where these two strings differ. A negative return value indicates that the first string would come before the second string if the strings are sorted in ascending order.

Try the following example, then modify strX arrays to your choice and see the result. If you want to compare first n characters of two strings, then strncmp can be used. Its return value is similar to strcmp. Employers: discover CodinGame for tech hiring. Log In Sign Up.

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Stack Overflow for Teams is a private, secure spot for you and your coworkers to find and share information. I am trying to get a program to let a user enter a word or character, store it, and then print it until the user types it again, exiting the program.

My code looks like this:. The problem is that I keep getting the printing of the input string, even when the input by the user check matches the original input. Am I comparing the two incorrectly? You can't usefully compare strings using! The reason for this is because! Not the contents of the strings themselves. Ok a few things: gets is unsafe and should be replaced with fgets input, sizeof inputstdin so that you don't get a buffer overflow.

Next, to compare strings, you must use strcmpwhere a return value of 0 indicates that the two strings match. Using the equality operators ie. Use strcmp.

string compare in c

This is in string. See this for an better explanation of what strcmp returns. You can check thisa tutorial on strcmp. You should compare them char-by-char; for this you can use a function and return a boolean True:1, False:0 value. Then you can use it in the test condition of the while loop.

Welcome to the concept of the pointer. Generations of beginning programmers have found the concept elusive, but if you wish to grow into a competent programmer, you must eventually master this concept — and moreover, you are already asking the right question. That's good. In the diagram, the integer 1 is stored in memory at address 0x Why at an address? Because memory is large and can store many integers, just as a city is large and can house many families.

Each integer is stored at a memory location, as each family resides in a house. Each memory location is identified by an addressas each house is identified by an address. The two boxes in the diagram represent two distinct memory locations. You can think of them as if they were houses. The integer 1 resides in the memory location at address 0x think, " Elm St.

The integer 7 resides in the memory location at address 0x think, " Elm St. You thought that your program was comparing the 1 to the 7, but it wasn't.Compares two specified String objects and returns an integer that indicates their relative position in the sort order. Compares two specified String objects, ignoring or honoring their case, and returns an integer that indicates their relative position in the sort order.

Compares two specified String objects using the specified rules, and returns an integer that indicates their relative position in the sort order. Compares two specified String objects, ignoring or honoring their case, and using culture-specific information to influence the comparison, and returns an integer that indicates their relative position in the sort order.

Compares two specified String objects using the specified comparison options and culture-specific information to influence the comparison, and returns an integer that indicates the relationship of the two strings to each other in the sort order. Compares substrings of two specified String objects and returns an integer that indicates their relative position in the sort order.

Compares substrings of two specified String objects, ignoring or honoring their case, and returns an integer that indicates their relative position in the sort order. Compares substrings of two specified String objects using the specified rules, and returns an integer that indicates their relative position in the sort order.

Compares substrings of two specified String objects, ignoring or honoring their case and using culture-specific information to influence the comparison, and returns an integer that indicates their relative position in the sort order. Compares substrings of two specified String objects using the specified comparison options and culture-specific information to influence the comparison, and returns an integer that indicates the relationship of the two substrings to each other in the sort order.

All overloads of the Compare method return a bit signed integer indicating the lexical relationship between the two comparands. Whenever possible, you should call an overload of the Compare method that includes a StringComparison parameter. For more information, see Best Practices for Using Strings. The following example calls the Compare String, String method to compare three sets of strings.

In the following example, the ReverseStringComparer class demonstrates how you can evaluate two strings with the Compare method. The comparison uses the current culture to obtain culture-specific information such as casing rules and the alphabetic order of individual characters.

For example, a culture could specify that certain combinations of characters be treated as a single character, or uppercase and lowercase characters be compared in a particular way, or that the sorting order of a character depends on the characters that precede or follow it.

The comparison is performed using word sort rules. For more information about word, string, and ordinal sorts, see System. When comparing strings, you should call the Compare String, String, StringComparison method, which requires that you explicitly specify the type of string comparison that the method uses.

One or both comparands can be null. By definition, any string, including the empty string ""compares greater than a null reference; and two null references compare equal to each other. The comparison terminates when an inequality is discovered or both strings have been compared.

However, if the two strings compare equal to the end of one string, and the other string has characters remaining, then the string with remaining characters is considered greater. The return value is the result of the last comparison performed. Unexpected results can occur when comparisons are affected by culture-specific casing rules.

For example, in Turkish, the following example yields the wrong results because the file system in Turkish does not use linguistic casing rules for the letter "i" in "file". Compare the path name to "file" using an ordinal comparison. The correct code to do this is as follows:. Character sets include ignorable characters.Code examples of compare strings in C using String. Equals, String. Compare, String. CompareTo method, and StringComparer.

C String. Compare method compares two strings in C. You can also use C String. Equals method and StringComparer class and its method. This article and code examples demonstrate how to compare strings in C using these different methods.

You may also want to check out Substrings in C to learn more about substrings. Using String. Equals method. If both strings are equal, the method returns true; else returns false. The code sample in Listing 1 is an example of comparing two strings using String. The output of Listing 1 looks like Figure 1.

Figure 1. Compare method compares two strings and returns an integer value. The return value of the Compare method can be less than zero, greater than zero or equals to zero. Return value Meaning Less than 0 The first string precedes the second string in the sort order. Geater than 0 The first string follows the second string in the sort order.

The code sample in Listing 2 is an example of comparing two strings using String. Compare method. It compares a value either a string or on object with a string instance. Return values of this method are same as the Compare method. The code sample in Listing 3 is an example of comparing two strings using the CompareTo method. The code sample in Listing 4 is an example of comparing two strings using the StringComparer. NET Core and C.

How to compare strings in C#

NET Core using different methods. View All. Mahesh Chand Updated date Sep 25, The simplest form of comparting two string for the same value is using String. CompareTo method is an instance method of string class. You can also use the StringComparer class to compare two strings. This article and code sample demonstrated how to comapre two strings in C and.This function takes two strings as arguments and compare these two strings lexicographically.

In the above prototype, function srtcmp takes two strings as parameters and returns an integer value based on the comparison of strings. This function can return three different integer values based on the comparison:. Important point : When the strings are not same, you will find that the value returned by the strcmp function is the difference between the ASCII values of first unmatched character in leftStr and rightStr in both the cases. This article is contributed by Harsh Agarwal. If you like GeeksforGeeks and would like to contribute, you can also write an article using contribute.

See your article appearing on the GeeksforGeeks main page and help other Geeks. Please write comments if you find anything incorrect, or you want to share more information about the topic discussed above. Attention reader! Writing code in comment?

Please use ide. If first character in both strings are equal, then this function will check the second character, if this is also equal then it will check the third and so on This process will be continued until a character in either string is NULL or the characters are unequal.

What does strcmp return? Load Comments. We use cookies to ensure you have the best browsing experience on our website.Depending on the requirement, C offers a few ways to compare strings. For example, if you only require to check whether two strings are the same ignoring case. Similarly, you may compare the strings based on linguistic and ordinal. The string Compare method can be used to see if two strings are the same or which string is greater in terms of ASCII value.

The Compare method returns three possible values as int :. See an example below to learn how it works. The following example uses two strings, out of which first two words are matched and the third is different. In order to understand how the Compare method works; whether it only checks the first word or later — this should make things clearer:. That means the first sentence is greater than second. The Equals method of the String is used to determine if two string objects are the same or not.

How to perform String Comparison in c programming language - by Sanjay Gupta

The Equals return a Boolean; True if strings are same and False otherwise. Following is an example of using the Equals method. For that, we have two string objects and see how these are compared:. Yes, the Equals method is case sensitive. If strings are same, it returns True otherwise false. As per official documentationthe CompareTo method checks this instance of the object with the specified string object. The CompareTo indicates whether the object instance precedes, follows or appears in the same position in the sort order as compared to the specified object string in this case.

The return value by CompareTo is an int type with these possibilities suppose String1 is compared to String2 :. In the following example, we have four string variables that are compared by using the CompareTo method.

The results show all the three possibilities as shown below:. WriteLine string. ReadLine. WriteLine "Both Strings are same! WriteLine "Strings are different! WriteLine "Same!By using our site, you acknowledge that you have read and understand our Cookie PolicyPrivacy Policyand our Terms of Service.

Stack Overflow for Teams is a private, secure spot for you and your coworkers to find and share information. Because argv[1] for instance is actually a pointer to the string.

So all you're doing is comparing pointers. In C because, in most contexts, an array "decays into a pointer to its first element". So, when you have the array "foobar" and use it in most contexts, it decays into a pointer:. What you want it to compare the contents of the array with something.

You can do that manually. In C, a string is usually an array of char, or a pointer to char which is nearly the same. What's usually referred to as a 'C string' is language independent as 'Pascal string' isit's the representation of strings as a null-terminated linear array of characters.

This is why you have to use library functions like strcmp to compare string values. It wont compare lexicographically. That's due to other facts. Strings are not native types in C. What you are comparing in that example are two pointers. One to your first argument, and the other is a static character array with the contents of "-hello". That is, it will return true if the two operands refer to the same string in memory.

Therefore, it's unsuitable for use in comparing strings lexicographically. Because C strings are array of characters. Learn more. Asked 9 years, 9 months ago.

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Rodrigo de Azevedo 7 7 silver badges 17 17 bronze badges. Carlo del Mundo Carlo del Mundo 2, 5 5 gold badges 28 28 silver badges 54 54 bronze badges. Surely this question is an exact duplicate.

string compare in c

Active Oldest Votes. Oliver Charlesworth Oliver Charlesworth k 26 26 gold badges silver badges bronze badges. Bart van Ingen Schenau Bart van Ingen Schenau 14k 3 3 gold badges 28 28 silver badges 40 40 bronze badges. Thanks for the heads up Overdrivr. Comment added to the code to make it clear.

string compare in c

Because there is no such thing as a C string. There is definitely a thing called a C string.

string compare in c

I don't know exactly what you mean. Perhaps that "There is no C string-type in the C language"? That's just abusing the term. What's described there is a null-terminated string, as opposed to a 'Pascal String', which gives the size as the first byte. There is a compiler feature that automatically converts text between double quotes " There are also string library functions, which operate on null-terminated arrays of char.

More properly, a string value is represented by a sequence of characters followed by a 0 terminator.


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