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I am having some difficulty locating information of comparing C strings. I understand that unlike C++, C does not support operator overloading, so I'm wondering if there is any way to check if one string is greater/less than another (e.g. str1 > str2)?
Thanks ahead of time for your responses. This is honestly one of the first times I have actually had to ask a question because I could not find a related post.
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In C, string values (including string literals) are represented as arrays of char followed by a 0 terminator, and you cannot use the == operator to compare array contents; the language simply doesn't define the operation.
In order to compare two strings, we can use String's strcmp() function. The strcmp() function is a C library function used to compare two strings in a lexicographical manner. The function returns 0 if both the strings are equal or the same. The input string has to be a char array of C-style string.
The comparison operators also work on strings. To see if two strings are equal you simply write a boolean expression using the equality operator.
In String, the == operator is used to comparing the reference of the given strings, depending on if they are referring to the same objects. When you compare two strings using == operator, it will return true if the string variables are pointing toward the same java object. Otherwise, it will return false .
There are several, each serving different purposes (omitting wide character variants for now).
strcmp – compares two strings, character by character (with the C notion of what strings are equal or not – that doesn't need to coincide with how humans think – see strcoll). There's a variant for comparing only the first at most n characters, strncmp.
strcasecmp – compares two strings, ignoring case. There's a variant for comparing only the first at most n characters, strncasecmp.
strcoll – compares two strings, observing the currently set locale (which is why it's called collation, not comparing in this case). If you want ss and ß to compare equal for a German audience, then this is what you should use.
Where you might write
if (string1 > string2) ...
in a language, you have to write
if (strmp(string1, string2) > 0) ...
in C. Essentially you move both operands into the function call, retain the comparison operator and compare with 0 instead.
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Use strcmp() in C.
for example if you want to compare two strings s1 and s2 then,
strcmp(s1,s2) will return 0 if they are equal, positive integer if s1 is greater than s2 and negative integer if s1 is lesser than s2.
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