Online Upper Case Converter

Well I try to read a file and change every word that's beginning with a lowercase to the same word beginning with an uppercase.

This is what i got:

#include <stdio.h>#include <stdlib.h>int main(){FILE *fp;int zeichen;fp = fopen("test.txt", "r+");if(fp == NULL){    printf("Die Datei konnte nicht geoeffnet werden.\n");}else{    fseek(fp, 0L, SEEK_SET);    zeichen = fgetc(fp);    while(zeichen != EOF){        if(zeichen == ' '){            fseek(fp, 1L, SEEK_CUR);            if(('a' <= zeichen) && (zeichen <= 'z')){                zeichen = fgetc(fp);                fputc(toupper(zeichen), fp);            }        }        zeichen = fgetc(fp);    }    zeichen = fgetc(fp);    fclose(fp);}return 0;}

My test.txt file does not change at all.

Any suggestions what i am doing wrong?

I need to match all capital letters only if they are in a middle of the word. For exmaple RegExr would have a match for letter E. someThings for letter T.If capital letter start at the start of of the word it should not match.

This regex almost match it, but it actually matches both lower case next to upper case letter.

/[a-z][A-Z]/g

For example for word RegExr, it matches gE, but I need to match only E.

update

Updated title to specify that this case happens in a sentence, not single word.

What I am currently trying to accomplish is to make the first and last letters of a word(s) uppercase.

Currently this is my function:

function ManipulateStr($input){    return strrev(ucwords(strrev($input)));}

However this only changes the last letter of every word to uppercase, now I'm trying to wrap my mind around how to also get the first letter of every word capitalized.

An example:

input: hello my friends

output: HellO MY FriendS

Perhaps I will have to use a substr? But how would that work seeing as I want this to be applicable to either multiple words or a single word?

I try to get all combination upper and lower case characters of string. For example my string is abc. I need to get result like this, all combinations for 3 characters of string: (2^0) x (2^1) x (2^2) = 8:

abcAbcABcABCaBCabCAbCaBc

My code is this but I have a problem, my code have duplicate cases and not return AbC and aBc:

<?phpfunction opposite_case($str) {     if(ctype_upper($str))     {         return strtolower($str);     }     else     {         return strtoupper($str);     } } $str = "abc";for($i = 0 ; $i < strlen($str) ; $i++){    for($j = 0 ; $j < strlen($str) ; $j++)     {        $str[$j] = opposite_case($str[$j]);        echo $str."<br>";     }}?>

C language:I would like to ask how to sort a string alphabetically with upper case letters before equivalent lower case letters.example:input: baBadxDoutput: aaBbDdx