June 2018 Update

Task/Reverse-a-string/Modula-2/reverse-a-string.mod2

@@ -0,0 +1,40 @@
+MODULE ReverseStr;
+FROM FormatString IMPORT FormatString;
+FROM Terminal IMPORT Write,WriteString,WriteLn,ReadChar;
+
+PROCEDURE WriteInt(n : INTEGER);
+VAR buf : ARRAY[0..15] OF CHAR;
+BEGIN
+    FormatString("%i", buf, n);
+    WriteString(buf)
+END WriteInt;
+
+PROCEDURE ReverseStr(in : ARRAY OF CHAR; VAR out : ARRAY OF CHAR);
+VAR ip,op : INTEGER;
+BEGIN
+    ip := 0;
+    op := 0;
+    WHILE in[ip] # 0C DO
+        INC(ip)
+    END;
+    DEC(ip);
+    WHILE ip>=0 DO
+        out[op] := in[ip];
+        INC(op);
+        DEC(ip)
+    END
+END ReverseStr;
+
+TYPE A = ARRAY[0..63] OF CHAR;
+VAR is,os : A;
+BEGIN
+    is := "Hello World";
+    ReverseStr(is, os);
+
+    WriteString(is);
+    WriteLn;
+    WriteString(os);
+    WriteLn;
+
+    ReadChar
+END ReverseStr.