The Sleep() function has a capital letter and also requires a certain library file to be included. I am using Dev-CPP/MingW compiler and it required that I use #include<windows.h>.
Also, you were complicating yourself where you didn't have to with your printing function so I reworked it to be simpler. Hopefully this will be of help to you and feel free to ask more questions.
Code:
#include <stdio.h>
#include <windows.h>
char strOriginal[50];
char strCopy[50];
void SlowPrint(char strArray[]) {
for(int i = 0; strArray[i] ; i++) { // Loop through our string array parameter
printf("%c", strArray[i]); // Print out the character the loop is at
Sleep(1000); // Wait for 1000 milliseconds
}
Sleep(2000); // Wait for 2000 milliseconds now that it has been typed
}
int main() {
while (1) { // Keep looping so the program doesn't simply close after one go
scanf("%s", strOriginal ); // Get the user to input a string
strcpy(strCopy, strOriginal); // Copy that string into a second variable
SlowPrint(strCopy); // Slowly print out the string
}
}