how do i write the following functions:can somebody help me with this programm?

`int lengthOfString(char *string);`

the longer the text that is given,the longer the text caculation

`int letsFactorise(int charCount);`

the length of the texts in order of prime number,if no prime numbers then give Error-code back.

`void createMatrix(char *string);`

the aready calculated prime numbers,the texts in transponetial matrix transformed.

`void getStdin();`

i can write till EOF(-1)