added print prompt function

src/c/ticTacToe.c

@@ -7,4 +7,8 @@
 
 int something(int a){
     return a;
+}
+
+void printPrompt(){
+    printf("Let's play Tic Tac Toe. You will use O, I will use X.\nJust enter the number of the field you choose.\nYou start.\n");
 }

src/c/ticTacToe.h

@@ -2,5 +2,6 @@
 #define TICTACTOE_H
 
 int something(int a);
+void printPrompt();
 
 #endif