diff --git a/Canon.Console/Extensions/RootCommandExtensions.cs b/Canon.Console/Extensions/RootCommandExtensions.cs
index 1017886..20ac288 100644
--- a/Canon.Console/Extensions/RootCommandExtensions.cs
+++ b/Canon.Console/Extensions/RootCommandExtensions.cs
@@ -4,6 +4,7 @@ using Canon.Console.Services;
 using Canon.Core.Abstractions;
 using Canon.Core.GrammarParser;
 using Canon.Core.LexicalParser;
+using Canon.Core.SemanticParser;
 using Microsoft.Extensions.DependencyInjection;
 using Microsoft.Extensions.Hosting;
 using Microsoft.Extensions.Logging;
@@ -39,6 +40,7 @@ public static class RootCommandExtensions
             builder.Services.AddSingleton<CompilerOption>(
                 _ => new CompilerOption { SourceFilename = sourceFilename });
             builder.Services.AddTransient<ILexer, Lexer>();
+            builder.Services.AddSingleton<SyntaxTreeTraveller>();
             builder.Services.AddSingleton<IGrammarParser>(_ => GeneratedGrammarParser.Instance);
             builder.Services.AddHostedService<Compiler>();
 
diff --git a/Canon.Console/Services/Compiler.cs b/Canon.Console/Services/Compiler.cs
index 594f43d..2c3138e 100644
--- a/Canon.Console/Services/Compiler.cs
+++ b/Canon.Console/Services/Compiler.cs
@@ -1,7 +1,7 @@
 using Canon.Console.Models;
 using Canon.Core.Abstractions;
-using Canon.Core.CodeGenerators;
 using Canon.Core.LexicalParser;
+using Canon.Core.SemanticParser;
 using Canon.Core.SyntaxNodes;
 using Microsoft.Extensions.Hosting;
 using Microsoft.Extensions.Logging;
@@ -12,6 +12,7 @@ public class Compiler(
     CompilerOption compilerOption,
     ILexer lexer,
     IGrammarParser grammarParser,
+    SyntaxTreeTraveller traveller,
     IHostApplicationLifetime applicationLifetime,
     ILogger<Compiler> logger) : IHostedService
 {
@@ -20,10 +21,10 @@ public class Compiler(
         IEnumerable<SemanticToken> tokens = lexer.Tokenize(await CreateSourceReader());
         ProgramStruct root = grammarParser.Analyse(tokens);
 
-        CCodeBuilder builder = new();
-        root.GenerateCCode(builder);
+        CCodeGenerateVisitor visitor = new();
+        traveller.Travel(root, visitor);
 
-        await WriteToOutputFile(builder.Build());
+        await WriteToOutputFile(visitor.Builder.Build());
         applicationLifetime.StopApplication();
     }
 
@@ -49,7 +50,7 @@ public class Compiler(
 
     private async Task WriteToOutputFile(string compiledCode)
     {
-        FileInfo outputFile = new(Path.Combine(Environment.CurrentDirectory,
+        FileInfo outputFile = new(Path.Combine(Path.GetDirectoryName(compilerOption.SourceFilename)!,
             Path.GetFileNameWithoutExtension(compilerOption.SourceFilename) + ".c"));
         logger.LogDebug("Select output file: '{}'.", outputFile.Name);
 
diff --git a/open_set/16_mod.pas b/open_set/16_mod.pas
index 9e8f5af..951c18c 100644
--- a/open_set/16_mod.pas
+++ b/open_set/16_mod.pas
@@ -3,5 +3,5 @@ var
   a: integer;
 begin
   a := 10;
-  write(a / 3);
+  write(a div 3);
 end.
diff --git a/open_set/46_full_conn.pas b/open_set/46_full_conn.pas
index 8de511e..e4f228d 100644
--- a/open_set/46_full_conn.pas
+++ b/open_set/46_full_conn.pas
@@ -13,7 +13,7 @@ end;
 
 function model: integer;
 begin
-    if (+relu_reg(+a[0][0] * 85 + a[0][1] * 23 + a[0][2] * -82 + a[0][3] * -103 + a[0][4] * -123 + a[1][0] * 64 + a[1][1] * -120 + a[1][2] * 50 + a[1][3] * -59 + a[1][4] * 47 + a[2][0] * -111 + a[2][1] * -67 + a[2][2] * -106 + a[2][3] * -75 + a[2][4] * -102 + a[3][0] * 34 + a[3][1] * -39 + a[3][2] * 65 + a[3][3] * 47 + a[3][4] * 113 + a[4][0] * 110 + a[4][1] * 47 + a[4][2] * -4 + a[4][3] * 80 + a[4][4] * 46) * 39 + relu_reg(+a[0][0] * -106 + a[0][1] * 126 + a[0][2] * -18 + a[0][3] * -31 + a[0][4] * -8 + a[1][0] * 47 + a[1][1] * -4 + a[1][2] * 67 + a[1][3] * -94 + a[1][4] * -121 + a[2][0] * 7 + a[2][1] * -21 + a[2][2] * -60 + a[2][3] * -43 + a[2][4] * 105 + a[3][0] * -42 + a[3][1] * 87 + a[3][2] * 29 + a[3][3] * -106 + a[3][4] * -31 + a[4][0] * -110 + a[4][1] * -100 + a[4][2] * -22 + a[4][3] * -75 + a[4][4] * -125) * 77 + relu_reg(+a[0][0] * 26 + a[0][1] * 76 + a[0][2] * -70 + a[0][3] * 29 + a[0][4] * -95 + a[1][0] * 96 + a[1][1] * 52 + a[1][2] * -68 + a[1][3] * -5 + a[1][4] * 34 + a[2][0] * -34 + a[2][1] * 102 + a[2][2] * 6 + a[2][3] * -38 + a[2][4] * 27 + a[3][0] * 110 + a[3][1] * 116 + a[3][2] * 39 + a[3][3] * -63 + a[3][4] * -99 + a[4][0] * 65 + a[4][1] * 120 + a[4][2] * -39 + a[4][3] * -6 + a[4][4] * 94) * 127 + relu_reg(+a[0][0] * -23 + a[0][1] * -63 + a[0][2] * 49 + a[0][3] * 50 + a[0][4] * 72 + a[1][0] * 85 + a[1][1] * -30 + a[1][2] * 12 + a[1][3] * 125 + a[1][4] * -117 + a[2][0] * -65 + a[2][1] * -67 + a[2][2] * 125 + a[2][3] * 110 + a[2][4] * -31 + a[3][0] * -123 + a[3][1] * 83 + a[3][2] * 122 + a[3][3] * 11 + a[3][4] * -23 + a[4][0] * -47 + a[4][1] * -32 + a[4][2] * -117 + a[4][3] * 95 + a[4][4] * 118) * -106 + relu_reg(+a[0][0] * 8 + a[0][1] * 82 + a[0][2] * -104 + a[0][3] * 101 + a[0][4] * -116 + a[1][0] * -63 + a[1][1] * -16 + a[1][2] * -70 + a[1][3] * 125 + a[1][4] * 75 + a[2][0] * 66 + a[2][1] * -96 + a[2][2] * -101 + a[2][3] * -114 + a[2][4] * 59 + a[3][0] * 12 + a[3][1] * 5 + a[3][2] * -95 + a[3][3] * 116 + a[3][4] * -93 + a[4][0] * 15 + a[4][1] * 79 + a[4][2] * 3 + a[4][3] * 49 + a[4][4] * -124) * -3 + relu_reg(+a[0][0] * 81 + a[0][1] * 68 + a[0][2] * -102 + a[0][3] * -74 + a[0][4] * 121 + a[1][0] * -15 + a[1][1] * 55 + a[1][2] * 101 + a[1][3] * -13 + a[1][4] * -62 + a[2][0] * 64 + a[2][1] * 114 + a[2][2] * 38 + a[2][3] * -21 + a[2][4] * 112 + a[3][0] * 114 + a[3][1] * 112 + a[3][2] * -10 + a[3][3] * -16 + a[3][4] * -50 + a[4][0] * -112 + a[4][1] * -116 + a[4][2] * -54 + a[4][3] * 82 + a[4][4] * -72) * 32 + relu_reg(+a[0][0] * 15 + a[0][1] * -77 + a[0][2] * 66 + a[0][3] * -90 + a[0][4] * -6 + a[1][0] * -30 + a[1][1] * -8 + a[1][2] * 81 + a[1][3] * 2 + a[1][4] * -110 + a[2][0] * -95 + a[2][1] * 59 + a[2][2] * 52 + a[2][3] * 15 + a[2][4] * 55 + a[3][0] * -33 + a[3][1] * 14 + a[3][2] * 58 + a[3][3] * 67 + a[3][4] * 86 + a[4][0] * -79 + a[4][1] * 48 + a[4][2] * -13 + a[4][3] * -15 + a[4][4] * 66) * -95 + relu_reg(+a[0][0] * 33 + a[0][1] * 82 + a[0][2] * 67 + a[0][3] * 30 + a[0][4] * -2 + a[1][0] * 65 + a[1][1] * 120 + a[1][2] * -13 + a[1][3] * 18 + a[1][4] * 5 + a[2][0] * 104 + a[2][1] * -119 + a[2][2] * -7 + a[2][3] * 71 + a[2][4] * 107 + a[3][0] * 24 + a[3][1] * 82 + a[3][2] * -96 + a[3][3] * -104 + a[3][4] * -121 + a[4][0] * 65 + a[4][1] * 97 + a[4][2] * 83 + a[4][3] * 46 + a[4][4] * -84) * -50 + relu_reg(+a[0][0] * -29 + a[0][1] * 7 + a[0][2] * -70 + a[0][3] * 38 + a[0][4] * -90 + a[1][0] * -15 + a[1][1] * -32 + a[1][2] * 37 + a[1][3] * 36 + a[1][4] * -62 + a[2][0] * -125 + a[2][1] * -46 + a[2][2] * -70 + a[2][3] * 37 + a[2][4] * -73 + a[3][0] * -34 + a[3][1] * -87 + a[3][2] * -75 + a[3][3] * 71 + a[3][4] * -77 + a[4][0] * 53 + a[4][1] * 37 + a[4][2] * -103 + a[4][3] * -13 + a[4][4] * -114) * -23 + relu_reg(+a[0][0] * 67 + a[0][1] * 42 + a[0][2] * 41 + a[0][3] * -123 + a[0][4] * -92 + a[1][0] * 10 + a[1][1] * -77 + a[1][2] * 75 + a[1][3] * 96 + a[1][4] * -51 + a[2][0] * 109 + a[2][1] * -74 + a[2][2] * -7 + a[2][3] * -122 + a[2][4] * 67 + a[3][0] * 47 + a[3][1] * 22 + a[3][2] * -68 + a[3][3] * 38 + a[3][4] * 29 + a[4][0] * 115 + a[4][1] * -121 + a[4][2] * 36 + a[4][3] * -49 + a[4][4] * 85) * 46 > 0) then
+    if (+relu_reg(+a[0, 0] * 85 + a[0, 1] * 23 + a[0, 2] * -82 + a[0, 3] * -103 + a[0, 4] * -123 + a[1, 0] * 64 + a[1, 1] * -120 + a[1, 2] * 50 + a[1, 3] * -59 + a[1, 4] * 47 + a[2, 0] * -111 + a[2, 1] * -67 + a[2, 2] * -106 + a[2, 3] * -75 + a[2, 4] * -102 + a[3, 0] * 34 + a[3, 1] * -39 + a[3, 2] * 65 + a[3, 3] * 47 + a[3, 4] * 113 + a[4, 0] * 110 + a[4, 1] * 47 + a[4, 2] * -4 + a[4, 3] * 80 + a[4, 4] * 46) * 39 + relu_reg(+a[0, 0] * -106 + a[0, 1] * 126 + a[0, 2] * -18 + a[0, 3] * -31 + a[0, 4] * -8 + a[1, 0] * 47 + a[1, 1] * -4 + a[1, 2] * 67 + a[1, 3] * -94 + a[1, 4] * -121 + a[2, 0] * 7 + a[2, 1] * -21 + a[2, 2] * -60 + a[2, 3] * -43 + a[2, 4] * 105 + a[3, 0] * -42 + a[3, 1] * 87 + a[3, 2] * 29 + a[3, 3] * -106 + a[3, 4] * -31 + a[4, 0] * -110 + a[4, 1] * -100 + a[4, 2] * -22 + a[4, 3] * -75 + a[4, 4] * -125) * 77 + relu_reg(+a[0, 0] * 26 + a[0, 1] * 76 + a[0, 2] * -70 + a[0, 3] * 29 + a[0, 4] * -95 + a[1, 0] * 96 + a[1, 1] * 52 + a[1, 2] * -68 + a[1, 3] * -5 + a[1, 4] * 34 + a[2, 0] * -34 + a[2, 1] * 102 + a[2, 2] * 6 + a[2, 3] * -38 + a[2, 4] * 27 + a[3, 0] * 110 + a[3, 1] * 116 + a[3, 2] * 39 + a[3, 3] * -63 + a[3, 4] * -99 + a[4, 0] * 65 + a[4, 1] * 120 + a[4, 2] * -39 + a[4, 3] * -6 + a[4, 4] * 94) * 127 + relu_reg(+a[0, 0] * -23 + a[0, 1] * -63 + a[0, 2] * 49 + a[0, 3] * 50 + a[0, 4] * 72 + a[1, 0] * 85 + a[1, 1] * -30 + a[1, 2] * 12 + a[1, 3] * 125 + a[1, 4] * -117 + a[2, 0] * -65 + a[2, 1] * -67 + a[2, 2] * 125 + a[2, 3] * 110 + a[2, 4] * -31 + a[3, 0] * -123 + a[3, 1] * 83 + a[3, 2] * 122 + a[3, 3] * 11 + a[3, 4] * -23 + a[4, 0] * -47 + a[4, 1] * -32 + a[4, 2] * -117 + a[4, 3] * 95 + a[4, 4] * 118) * -106 + relu_reg(+a[0, 0] * 8 + a[0, 1] * 82 + a[0, 2] * -104 + a[0, 3] * 101 + a[0, 4] * -116 + a[1, 0] * -63 + a[1, 1] * -16 + a[1, 2] * -70 + a[1, 3] * 125 + a[1, 4] * 75 + a[2, 0] * 66 + a[2, 1] * -96 + a[2, 2] * -101 + a[2, 3] * -114 + a[2, 4] * 59 + a[3, 0] * 12 + a[3, 1] * 5 + a[3, 2] * -95 + a[3, 3] * 116 + a[3, 4] * -93 + a[4, 0] * 15 + a[4, 1] * 79 + a[4, 2] * 3 + a[4, 3] * 49 + a[4, 4] * -124) * -3 + relu_reg(+a[0, 0] * 81 + a[0, 1] * 68 + a[0, 2] * -102 + a[0, 3] * -74 + a[0, 4] * 121 + a[1, 0] * -15 + a[1, 1] * 55 + a[1, 2] * 101 + a[1, 3] * -13 + a[1, 4] * -62 + a[2, 0] * 64 + a[2, 1] * 114 + a[2, 2] * 38 + a[2, 3] * -21 + a[2, 4] * 112 + a[3, 0] * 114 + a[3, 1] * 112 + a[3, 2] * -10 + a[3, 3] * -16 + a[3, 4] * -50 + a[4, 0] * -112 + a[4, 1] * -116 + a[4, 2] * -54 + a[4, 3] * 82 + a[4, 4] * -72) * 32 + relu_reg(+a[0, 0] * 15 + a[0, 1] * -77 + a[0, 2] * 66 + a[0, 3] * -90 + a[0, 4] * -6 + a[1, 0] * -30 + a[1, 1] * -8 + a[1, 2] * 81 + a[1, 3] * 2 + a[1, 4] * -110 + a[2, 0] * -95 + a[2, 1] * 59 + a[2, 2] * 52 + a[2, 3] * 15 + a[2, 4] * 55 + a[3, 0] * -33 + a[3, 1] * 14 + a[3, 2] * 58 + a[3, 3] * 67 + a[3, 4] * 86 + a[4, 0] * -79 + a[4, 1] * 48 + a[4, 2] * -13 + a[4, 3] * -15 + a[4, 4] * 66) * -95 + relu_reg(+a[0, 0] * 33 + a[0, 1] * 82 + a[0, 2] * 67 + a[0, 3] * 30 + a[0, 4] * -2 + a[1, 0] * 65 + a[1, 1] * 120 + a[1, 2] * -13 + a[1, 3] * 18 + a[1, 4] * 5 + a[2, 0] * 104 + a[2, 1] * -119 + a[2, 2] * -7 + a[2, 3] * 71 + a[2, 4] * 107 + a[3, 0] * 24 + a[3, 1] * 82 + a[3, 2] * -96 + a[3, 3] * -104 + a[3, 4] * -121 + a[4, 0] * 65 + a[4, 1] * 97 + a[4, 2] * 83 + a[4, 3] * 46 + a[4, 4] * -84) * -50 + relu_reg(+a[0, 0] * -29 + a[0, 1] * 7 + a[0, 2] * -70 + a[0, 3] * 38 + a[0, 4] * -90 + a[1, 0] * -15 + a[1, 1] * -32 + a[1, 2] * 37 + a[1, 3] * 36 + a[1, 4] * -62 + a[2, 0] * -125 + a[2, 1] * -46 + a[2, 2] * -70 + a[2, 3] * 37 + a[2, 4] * -73 + a[3, 0] * -34 + a[3, 1] * -87 + a[3, 2] * -75 + a[3, 3] * 71 + a[3, 4] * -77 + a[4, 0] * 53 + a[4, 1] * 37 + a[4, 2] * -103 + a[4, 3] * -13 + a[4, 4] * -114) * -23 + relu_reg(+a[0, 0] * 67 + a[0, 1] * 42 + a[0, 2] * 41 + a[0, 3] * -123 + a[0, 4] * -92 + a[1, 0] * 10 + a[1, 1] * -77 + a[1, 2] * 75 + a[1, 3] * 96 + a[1, 4] * -51 + a[2, 0] * 109 + a[2, 1] * -74 + a[2, 2] * -7 + a[2, 3] * -122 + a[2, 4] * 67 + a[3, 0] * 47 + a[3, 1] * 22 + a[3, 2] * -68 + a[3, 3] * 38 + a[3, 4] * 29 + a[4, 0] * 115 + a[4, 1] * -121 + a[4, 2] * 36 + a[4, 3] * -49 + a[4, 4] * 85) * 46 > 0) then
         model := 1
     else
         model := 0;
diff --git a/open_set/55_long_array2.pas b/open_set/55_long_array2.pas
index 88cc7a8..3d9b3bc 100644
--- a/open_set/55_long_array2.pas
+++ b/open_set/55_long_array2.pas
@@ -15,16 +15,16 @@ begin
 end;
 
 begin
-  b[1][0] := 1;
-  b[2][0] := 2;
-  b[2][1] := 3;
-  b[3][0] := 4;
-  b[3][1] := 5;
-  b[3][2] := 6;
-  c[0][0] := 1;
-  c[0][1] := 2;
-  c[1][0] := 3;
-  c[1][1] := 4;
+  b[1, 0] := 1;
+  b[2, 0] := 2;
+  b[2, 1] := 3;
+  b[3, 0] := 4;
+  b[3, 1] := 5;
+  b[3, 2] := 6;
+  c[0, 0] := 1;
+  c[0, 1] := 2;
+  c[1, 0] := 3;
+  c[1, 1] := 4;
   write(f1);
-  write(c[2][0]);
+  write(c[2, 0]);
 end.
diff --git a/open_set/57_many_params.pas b/open_set/57_many_params.pas
index c78c2fb..2e2fe03 100644
--- a/open_set/57_many_params.pas
+++ b/open_set/57_many_params.pas
@@ -19,38 +19,38 @@ end;
 function param32_arr: integer;
 var sum: integer;
 begin
-    sum := arr[0][0] + arr[0][1];
-    sum := sum + arr[1][0] + arr[1][1];
-    sum := sum + arr[2][0] + arr[2][1];
-    sum := sum + arr[3][0] + arr[3][1];
-    sum := sum + arr[4][0] + arr[4][1];
-    sum := sum + arr[5][0] + arr[5][1];
-    sum := sum + arr[6][0] + arr[6][1];
-    sum := sum + arr[7][0] + arr[7][1];
-    sum := sum + arr[8][0] + arr[8][1];
-    sum := sum + arr[9][0] + arr[9][1];
-    sum := sum + arr[10][0] + arr[10][1];
-    sum := sum + arr[11][0] + arr[11][1];
-    sum := sum + arr[12][0] + arr[12][1];
-    sum := sum + arr[13][0] + arr[13][1];
-    sum := sum + arr[14][0] + arr[14][1];
-    sum := sum + arr[15][0] + arr[15][1];
-    sum := sum + arr[16][0] + arr[16][1];
-    sum := sum + arr[17][0] + arr[17][1];
-    sum := sum + arr[18][0] + arr[18][1];
-    sum := sum + arr[19][0] + arr[19][1];
-    sum := sum + arr[20][0] + arr[20][1];
-    sum := sum + arr[21][0] + arr[21][1];
-    sum := sum + arr[22][0] + arr[22][1];
-    sum := sum + arr[23][0] + arr[23][1];
-    sum := sum + arr[24][0] + arr[24][1];
-    sum := sum + arr[25][0] + arr[25][1];
-    sum := sum + arr[26][0] + arr[26][1];
-    sum := sum + arr[27][0] + arr[27][1];
-    sum := sum + arr[28][0] + arr[28][1];
-    sum := sum + arr[29][0] + arr[29][1];
-    sum := sum + arr[30][0] + arr[30][1];
-    sum := sum + arr[31][0] + arr[31][1];
+    sum := arr[0, 0] + arr[0, 1];
+    sum := sum + arr[1, 0] + arr[1, 1];
+    sum := sum + arr[2, 0] + arr[2, 1];
+    sum := sum + arr[3, 0] + arr[3, 1];
+    sum := sum + arr[4, 0] + arr[4, 1];
+    sum := sum + arr[5, 0] + arr[5, 1];
+    sum := sum + arr[6, 0] + arr[6, 1];
+    sum := sum + arr[7, 0] + arr[7, 1];
+    sum := sum + arr[8, 0] + arr[8, 1];
+    sum := sum + arr[9, 0] + arr[9, 1];
+    sum := sum + arr[10, 0] + arr[10, 1];
+    sum := sum + arr[11, 0] + arr[11, 1];
+    sum := sum + arr[12, 0] + arr[12, 1];
+    sum := sum + arr[13, 0] + arr[13, 1];
+    sum := sum + arr[14, 0] + arr[14, 1];
+    sum := sum + arr[15, 0] + arr[15, 1];
+    sum := sum + arr[16, 0] + arr[16, 1];
+    sum := sum + arr[17, 0] + arr[17, 1];
+    sum := sum + arr[18, 0] + arr[18, 1];
+    sum := sum + arr[19, 0] + arr[19, 1];
+    sum := sum + arr[20, 0] + arr[20, 1];
+    sum := sum + arr[21, 0] + arr[21, 1];
+    sum := sum + arr[22, 0] + arr[22, 1];
+    sum := sum + arr[23, 0] + arr[23, 1];
+    sum := sum + arr[24, 0] + arr[24, 1];
+    sum := sum + arr[25, 0] + arr[25, 1];
+    sum := sum + arr[26, 0] + arr[26, 1];
+    sum := sum + arr[27, 0] + arr[27, 1];
+    sum := sum + arr[28, 0] + arr[28, 1];
+    sum := sum + arr[29, 0] + arr[29, 1];
+    sum := sum + arr[30, 0] + arr[30, 1];
+    sum := sum + arr[31, 0] + arr[31, 1];
     param32_arr := sum;
 end;
 
diff --git a/open_set/64_nested_loops.pas b/open_set/64_nested_loops.pas
index 4330853..a122cfe 100644
--- a/open_set/64_nested_loops.pas
+++ b/open_set/64_nested_loops.pas
@@ -22,7 +22,7 @@ for a := 0 to x-1 do
             begin
               for g := 0 to 1 do
               begin
-                arr1[a][b][c][d][e][f][g] := a + b + c + d + e + f + g + x + y;
+                arr1[a, b, c, d, e, f, g] := a + b + c + d + e + f + g + x + y;
               end;
             end;
           end;
@@ -50,7 +50,7 @@ for a := 0 to 9 do
             begin
               for g := 0 to 6 do
               begin
-                arr2[a][b][c][d][e][f][g] := a + b + d + g;
+                arr2[a, b, c, d, e, f, g] := a + b + d + g;
               end;
             end;
           end;
@@ -78,7 +78,7 @@ ans := 0;
             begin
               for g := 0 to n-1 do
               begin
-                ans := (ans mod 817) + arr1[a][b][c][d][e][f][g] + arr2[a][b][c][d][e][f][g];
+                ans := (ans mod 817) + arr1[a, b, c, d, e, f, g] + arr2[a, b, c, d, e, f, g];
               end;
             end;
           end;
diff --git a/open_set/65_float.pas b/open_set/65_float.pas
index d324c14..28b7c6d 100644
--- a/open_set/65_float.pas
+++ b/open_set/65_float.pas
@@ -21,7 +21,7 @@ end;
 
 function circle_area(radius: integer):real;
 begin
-  circle_area := PI * radius *radius + (radius * radius) * PI / 2;
+  circle_area := (PI * radius *radius + (radius * radius) * PI) / 2;
 end;
 
 function float_eq(a,b: real):integer;
@@ -32,12 +32,12 @@ begin
     float_eq := 0
 end;
 
-procedure error;
+procedure error();
 begin
   write(e);
 end;
 
-procedure ok;
+procedure ok();
 begin
   write(o);
 end;
@@ -45,27 +45,27 @@ end;
 procedure assert(cond: integer);
 begin 
   if cond = 0 then
-    error
+    error()
   else
-    ok;
+    ok();
 end;
 
 begin
   assert(float_eq(circle_area(5), circle_area(FIVE)));
   if 1.5 <> 0.0 then
-    ok;
+    ok();
   if (not (3.3 = 0.0)) then
-    ok;
+    ok();
   if (0.0 <> 0.0) and (3 <> 0.0) then
-    error;
+    error();
   if (0 <> 0.0) or (0.3 <> 0.0) then
-    ok;
+    ok();
 
   p := 0;
   arr[0] := 1.0;
   arr[1] := 2.0;
   input := 0.520;
-  area := PI * input;
+  area := PI * input * input;
   area_trunc := circle_area(0);
   arr[p] := arr[p] + input;