Added assignment 7.

modsim/ass2/.gitignore

@@ -3,4 +3,6 @@ q2
 q3
 q4
 q5
+q6
+q7
 *.o

modsim/ass2/Makefile

@@ -2,7 +2,7 @@ CC=clang
 CFLAGS=-Wall -Wextra -pedantic -std=c99 -D_GNU_SOURCE
 LFLAGS=-lm
 
-all: q1 q2 q3 q4 q5
+all: q1 q2 q3 q4 q5 q7
 
 q%: q%.o
 	$(CC) $(CFLAGS) $(LFLAGS) -o $@ $^
@@ -11,7 +11,7 @@ q%: q%.o
 	$(CC) $(CFLAGS) -o $@ -c $^
 
 clean:
-	for i in `seq 6`; do \
+	for i in `seq 7`; do \
 		rm -vf q$$i; \
 	done;
 	rm -vf *.o

modsim/ass2/q7.c

+/*
+ * Usage: ./q7 [ generations [ max_age ] ]
+ */
+
+#include <stdlib.h>
+#include <stdio.h>
+
+typedef struct rabbit {
+    int age;
+    struct rabbit *prev, *next;
+} rabbit;
+
+rabbit *rabbits = NULL;
+int rabbit_count = 0;
+
+rabbit *rabbit_born() {
+    rabbit *r = (rabbit*) malloc(sizeof(rabbit));
+
+    if( (r->next = rabbits) )
+        rabbits->prev = r;
+
+    r->age = 0;
+    rabbits = r;
+    rabbit_count++;
+
+    return r;
+}
+
+void rabbit_die(rabbit **ptr) {
+    rabbit *r = *ptr;
+
+    if( r->prev != NULL )
+        r->prev->next = r->next;
+
+    if( r->next != NULL )
+        r->next->prev = r->prev;
+
+    if( r == rabbits )
+        rabbits = NULL;
+
+    *ptr = NULL;
+    rabbit_count--;
+    free(r);
+}
+
+void sequence(int generations, int max_age) {
+    int i;
+    rabbit *r, *next = NULL;
+
+    printf("0");
+    rabbits = rabbit_born();
+
+    for( i = 1; i < generations; i++ ) {
+        for( r = rabbits; r != NULL; r = next ) {
+            next = r->next;
+
+            if( r->age++ ) {
+                rabbit_born();
+
+                if( r->age == max_age )
+                    rabbit_die(&r);
+            }
+        }
+
+        printf(" %d", rabbit_count);
+    }
+
+    puts("");
+
+    while( rabbits )
+        rabbit_die(&rabbits);
+}
+
+void sequence_old(int n) {
+    int i, new = 1, new_new, mature = 0, died = 0;
+
+    for( i = 0; i < n; i++ ) {
+        printf("%d + %d = %d\n", mature, new, new + mature);
+
+        new_new = mature;
+        mature = mature + new - died;
+        new = new_new;
+    }
+}
+
+int main(int argc, char *argv[]) {
+    int max_age = 0, generations = 10;
+
+    if( argc > 1 ) {
+        generations = atoi(argv[1]);
+
+        if( argc > 2 )
+            max_age = atoi(argv[2]);
+    }
+
+    sequence(generations, max_age);
+}