Case Insensitive compare

You are overcomplicating things.

I think you should consider looking for a good book on programming in C - it seems like you are not familiar with C or C++.

By the way - is your posted source code a verbatim copy, or have you typed in the code again? The warning is about stricmp, I can't see any calls to stricmp - just a call to lwrbuffer() and strcmp(). My guess is that you hand-typed, and that the strcmp() should be stricmp(). Never type in the code when posting. Always select all code and then copy/paste. I repeat: Always copy/paste!

Anyway, this is a very incomplete list with problems in your program:

In main(), you are calling lwrbuffer() without having declared the prototype. Any functions that you create must either have their function body above the function that calls it, our you must explicitly add a function prototype - either at top of the source file or in one of your include files.

lwrbuffer() has return type void, which doesn't mean "returns any type" but means "does not return anything". So, you can't in main() just typecast the return from lwrbuffer() to (char*). There is nothing returned!

lwrbuffer() has return type void, but still contains code of the type return <value>. A function with return type void must either be without any return statement, or may only contain empty return statements, i.e.

void fnk(void) {
    return;
}

lwrbuffer() is using old K&R-style parameter declaration, i.e. only the parameter name is specified. An you are following that up by the parameter being implied int. Your code should be:

char* lwrbuffer(const char* checkbody) {
    ...
}

By the way - why calling the parameter checkbody? A function called lwrbuffer by definition should not need to know WHY you convert a string to lowercase - so why should the parameter imply that it is for some form of check?

main() constains the following code:

char *path= "hello";
textBody = (char*)strchr(path,'\0');
textBody++;
strcpy(textbody2,textBody);

You first locate the terminating zero of the "hello" string, and then steps one step past. What do you expect to find there? That is an undefined memory location, so you can/must not try to perform that strcpy() operation!

You have the following line:

scanf("%d", &n);

It is expected to get characters from stdin (which may be an interesting concept for an embedded system) and scan for an integer. Shouldn't you check the return value of scanf() to see if an integer was received?

You are making quite a lot of copying - why? You can compare two strings on-the-fly without any copying. Just use two character pointers - one for each string. Convert the first character from each pointer to upper (or lower) case and compare. If different, you have an answer. If not different but any of the pointers point to a '\0' then you have reached the end of both strings, and they where equal. If not different and neither pointer pointed to '\0', then step both pointers forward one step and repeat. Quick and easy with just a couple of code lines and no extra buffer space needed. Also, the comparison code will terminate as soon as possible in case the strings where not identical - why convert the full string to lowercase if it was enough to look at the first character?

your code:

for (;i <= strlen(checkbody);i++) {}

will call strlen() once for every character in checkbody(). And strlen() will then have to step through every character in checkbody... For a 100-character string, the inner loop in strlen() will have to step 100*100 = 10000 times! No need for an O(n^2) solution to an O(n) problem. No need for a separate loop variable or knowing the length of the string. Since you are scanning through the string one character at the time anyway - just let the loop end when the current character is '\0'.

The lwrbuffer() function is converting the input string to lowercase in-place. So why are you at the same time assigning the lower-case conversion into the lowertextBody variable? Also note that the lowertextBody pointer has never been assigned an initial value, so it doesn't point to a buffer that can store any values.

You continue with even one more "extra" string copy, doing:

strcpy (lwrtext,lowertextBody);

But this time too, the lwrtext pointer hasn't been initialized, so there are no buffer to store the string.

I really, really recommend that you pick up a good book on C - you can't do embedded programming if you are not comfortable writing code on a PC.

Drop your over-complicated code and sit down a bit and think about implementing a stricmp() yourself. I have already mentioned the required steps in the algorithm. They are few. They are simple. So the stricmp() function must by deduction also be simple.

You are overcomplicating things.

I think you should consider looking for a good book on programming in C - it seems like you are not familiar with C or C++.

By the way - is your posted source code a verbatim copy, or have you typed in the code again? The warning is about stricmp, I can't see any calls to stricmp - just a call to lwrbuffer() and strcmp(). My guess is that you hand-typed, and that the strcmp() should be stricmp(). Never type in the code when posting. Always select all code and then copy/paste. I repeat: Always copy/paste!

Anyway, this is a very incomplete list with problems in your program:

In main(), you are calling lwrbuffer() without having declared the prototype. Any functions that you create must either have their function body above the function that calls it, our you must explicitly add a function prototype - either at top of the source file or in one of your include files.

lwrbuffer() has return type void, which doesn't mean "returns any type" but means "does not return anything". So, you can't in main() just typecast the return from lwrbuffer() to (char*). There is nothing returned!

lwrbuffer() has return type void, but still contains code of the type return <value>. A function with return type void must either be without any return statement, or may only contain empty return statements, i.e.

void fnk(void) {
    return;
}

lwrbuffer() is using old K&R-style parameter declaration, i.e. only the parameter name is specified. An you are following that up by the parameter being implied int. Your code should be:

char* lwrbuffer(const char* checkbody) {
    ...
}

By the way - why calling the parameter checkbody? A function called lwrbuffer by definition should not need to know WHY you convert a string to lowercase - so why should the parameter imply that it is for some form of check?

main() constains the following code:

char *path= "hello";
textBody = (char*)strchr(path,'\0');
textBody++;
strcpy(textbody2,textBody);

You first locate the terminating zero of the "hello" string, and then steps one step past. What do you expect to find there? That is an undefined memory location, so you can/must not try to perform that strcpy() operation!

You have the following line:

scanf("%d", &n);

It is expected to get characters from stdin (which may be an interesting concept for an embedded system) and scan for an integer. Shouldn't you check the return value of scanf() to see if an integer was received?

You are making quite a lot of copying - why? You can compare two strings on-the-fly without any copying. Just use two character pointers - one for each string. Convert the first character from each pointer to upper (or lower) case and compare. If different, you have an answer. If not different but any of the pointers point to a '\0' then you have reached the end of both strings, and they where equal. If not different and neither pointer pointed to '\0', then step both pointers forward one step and repeat. Quick and easy with just a couple of code lines and no extra buffer space needed. Also, the comparison code will terminate as soon as possible in case the strings where not identical - why convert the full string to lowercase if it was enough to look at the first character?

your code:

for (;i <= strlen(checkbody);i++) {}

will call strlen() once for every character in checkbody(). And strlen() will then have to step through every character in checkbody... For a 100-character string, the inner loop in strlen() will have to step 100*100 = 10000 times! No need for an O(n^2) solution to an O(n) problem. No need for a separate loop variable or knowing the length of the string. Since you are scanning through the string one character at the time anyway - just let the loop end when the current character is '\0'.

The lwrbuffer() function is converting the input string to lowercase in-place. So why are you at the same time assigning the lower-case conversion into the lowertextBody variable? Also note that the lowertextBody pointer has never been assigned an initial value, so it doesn't point to a buffer that can store any values.

You continue with even one more "extra" string copy, doing:

strcpy (lwrtext,lowertextBody);

But this time too, the lwrtext pointer hasn't been initialized, so there are no buffer to store the string.

I really, really recommend that you pick up a good book on C - you can't do embedded programming if you are not comfortable writing code on a PC.

Drop your over-complicated code and sit down a bit and think about implementing a stricmp() yourself. I have already mentioned the required steps in the algorithm. They are few. They are simple. So the stricmp() function must by deduction also be simple.