Initial data commit

Task/Subtractive-generator/Seed7/subtractive-generator.seed7

@@ -0,0 +1,54 @@
+$ include "seed7_05.s7i";
+
+const integer: MOD is 1000000000;
+
+const type: subtractiveGenerator is new struct
+    var array integer: state is [0 .. 54] times 0;
+    var integer: si is 0;
+    var integer: sj is 24;
+  end struct;
+
+const func integer: subrand (inout subtractiveGenerator: generator) is forward;
+
+const func subtractiveGenerator: subrandSeed (in var integer: p1) is func
+  result
+    var subtractiveGenerator: generator is subtractiveGenerator.value;
+  local
+    var integer: p2 is 1;
+    var integer: i is 0;
+    var integer: j is 21;
+  begin
+    generator.state[0] := p1 mod MOD;
+    for i range 1 to 54 do
+      generator.state[j] := p2;
+      p2 := (p1 - p2) mod MOD;
+      p1 := generator.state[j];
+      j := (j + 21) mod 55;
+    end for;
+    for i range 1 to 165 do
+      ignore(subrand(generator));
+    end for;
+  end func;
+
+const func integer: subrand (inout subtractiveGenerator: generator) is func
+  result
+    var integer: subrand is 0;
+  begin
+    if generator.si = generator.sj then
+      generator := subrandSeed(0);
+    end if;
+    generator.si := pred(generator.si) mod 55;
+    generator.sj := pred(generator.sj) mod 55;
+    subrand := (generator.state[generator.si] - generator.state[generator.sj]) mod MOD;
+    generator.state[generator.si] := subrand;
+  end func;
+
+const proc: main is func
+  local
+    var subtractiveGenerator: gen is subrandSeed(292929);
+    var integer: i is 0;
+  begin
+    for i range 1 to 10 do
+      writeln(subrand(gen));
+    end for;
+  end func;