Exercises

ashishlal · Nov 1, 2012 · 8a1edb0 · 8a1edb0
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diff --git a/11_3.cpp b/11_3.cpp
@@ -0,0 +1,26 @@
+#include <iostream>
+
+using namespace std;
+class INT {
+public:
+    INT() {};
+    INT(int j) {i=j;};
+    INT(const INT &j) {i=j.i;};
+    int operator+ (int j) { return i + j; };
+    int operator+ (INT k) { return i + k.i; };
+    int operator++ () { return ++i; };
+    int operator+= (int j) { return i+=j; };
+    INT operator= (int j) { i=j; return *this; };
+    INT operator= (INT j) { i=j.i; return *this; };
+    operator int() { return i; };
+private:
+    int i;
+};
+int main()
+{
+    INT a = 10;
+    cout << a << endl;
+    cout << a+1 << endl;
+    a+=1;
+    cout << a << endl;
+}
diff --git a/11_5.cpp b/11_5.cpp
@@ -0,0 +1,16 @@
+#include <iostream>
+
+using namespace std;
+
+class LINT {
+public:
+    LINT(int i) { 
+    }
+private:
+    char i[64];
+};
+
+int main()
+{
+
+}
diff --git a/11_7.cpp b/11_7.cpp
@@ -0,0 +1,102 @@
+#include <iostream>
+#include <cstdlib>
+#include <cstring>
+
+class String {
+    struct Srep {
+        char *s;
+        int sz;    // number of characters
+        int n;     // reference count
+        Srep(int nsz, const char *p) {
+            n = 1;
+            sz = nsz;
+            s = new char[sz + 1];
+            strcpy(s, p);
+        }
+        ~Srep() { delete [] s; }
+        Srep *get_own_copy()
+        {
+            if(n == 1) return this;
+            n--;
+            return new Srep(sz, s);
+        }
+        void assign(int nsz, const char *p)
+        {
+            if(sz != nsz) {
+               delete [] s;
+               sz = nsz;
+               s = new char[sz + 1];
+            }
+            strcpy(s,p);
+        }
+    };
+    Srep *rep;
+public:
+    String() { rep = new Srep(0, ""); };
+    String(const String &x) { x.rep->n++; rep = x.rep; };
+    ~String() { if(--rep->n == 0) delete rep; };
+    String & operator=(const String &x)
+    {
+         x.rep->n++;
+         if(--rep->n == 0) delete rep;
+         rep = x.rep;
+         return *this;
+    };
+    String(const char *s) { rep = new Srep(strlen(s), s); }
+    String & operator=(const char *s)
+    {
+        if(rep->n == 1)
+            rep->assign(strlen(s),s);
+        else {
+            rep->n--;
+            rep = new Srep(strlen(s), s);
+        }    
+        return *this;
+    }
+    void check(int i) const {  
+        if (i < 0 || rep->sz <= i) std::cout << "bad" << std::endl;
+    }
+    char read(int i) const { return rep->s[i]; }
+    char operator[](int i) const { return rep->s[i]; }
+    int size() const { return rep->sz; }
+};
+
+class String_iter {
+    // refer to string and string element
+public:
+    String_iter(String &s); // iterator for s
+    char &get() { c = str[elemptr]; return c; };   // reference to curr element
+    char &next();   // reference to next element
+    bool hasNext();   // reference to next element
+private:
+    unsigned int elemptr; // ptr to current element
+    String str;
+    char c;
+};
+
+String_iter::String_iter(String &s)
+{
+    elemptr = 0;
+    str = s;
+}
+char & String_iter::next()
+{
+    elemptr++;
+    c = str[elemptr];
+    return c;
+}
+
+bool String_iter::hasNext()
+{
+    bool ret = (elemptr < str.size())? true: false;
+    return ret;
+}
+
+int main()
+{
+    String s("hello world");
+    String_iter itr(s);
+    for(char c = itr.get(); itr.hasNext(); c = itr.next()) {
+        std::cout << c << std::endl;
+    }
+}
diff --git a/11_8.cpp b/11_8.cpp
@@ -0,0 +1,120 @@
+#include <iostream>
+#include <cstdlib>
+#include <cstring>
+
+class String {
+    struct Srep {
+        char *s;
+        int sz;    // number of characters
+        int n;     // reference count
+        Srep(int nsz, const char *p) {
+            n = 1;
+            sz = nsz;
+            s = new char[sz + 1];
+            strcpy(s, p);
+        }
+        ~Srep() { delete [] s; }
+        Srep *get_own_copy()
+        {
+            if(n == 1) return this;
+            n--;
+            return new Srep(sz, s);
+        }
+        void assign(int nsz, const char *p)
+        {
+            if(sz != nsz) {
+               delete [] s;
+               sz = nsz;
+               s = new char[sz + 1];
+            }
+            strcpy(s,p);
+        }
+    };
+    Srep *rep;
+public:
+    String() { rep = new Srep(0, ""); };
+    String(int a, int b) { rep = new Srep(b-a, ""); };
+    String(const String &x) { x.rep->n++; rep = x.rep; };
+    ~String() { if(--rep->n == 0) delete rep; };
+    String & operator=(const String &x)
+    {
+         x.rep->n++;
+         if(--rep->n == 0) delete rep;
+         rep = x.rep;
+         return *this;
+    };
+    String(const char *s) { rep = new Srep(strlen(s), s); }
+    String & operator=(const char *s)
+    {
+        if(rep->n == 1)
+            rep->assign(strlen(s),s);
+        else {
+            rep->n--;
+            rep = new Srep(strlen(s), s);
+        }    
+        return *this;
+    }
+    void check(int i) const {  
+        if (i < 0 || rep->sz <= i) std::cout << "bad" << std::endl;
+    }
+    char read(int i) const { return rep->s[i]; }
+    void write(int i, char c) const { rep->s[i]=c; }
+    char operator[](int i) const { return rep->s[i]; }
+    int size() const { return rep->sz; }
+    String & operator() (int a, int b)
+    {
+        if(a >= b) return *this;
+        if(b >= size()) return *this;
+        String *s = new String(a, b);
+        for(int i=0; i < (b-a); i++) {
+           s->write(i, rep->s[a+i]);
+        }
+        return *s;
+    }
+};
+
+class String_iter {
+    // refer to string and string element
+public:
+    String_iter(String &s); // iterator for s
+    char &get() { c = str[elemptr]; return c; };   // reference to curr element
+    char &next();   // reference to next element
+    bool hasNext();   // reference to next element
+private:
+    unsigned int elemptr; // ptr to current element
+    String str;
+    char c;
+};
+
+String_iter::String_iter(String &s)
+{
+    elemptr = 0;
+    str = s;
+}
+char & String_iter::next()
+{
+    elemptr++;
+    c = str[elemptr];
+    return c;
+}
+
+bool String_iter::hasNext()
+{
+    bool ret = (elemptr < str.size())? true: false;
+    return ret;
+}
+
+int main()
+{
+    String s("hello world");
+    String_iter itr(s);
+    for(char c = itr.get(); itr.hasNext(); c = itr.next()) {
+        std::cout << c << std::endl;
+    }
+    std::cout << "" << std::endl;
+    String s1(s(0, 5));
+    String_iter itr1(s1);
+    for(char c = itr1.get(); itr1.hasNext(); c = itr1.next()) {
+        std::cout << c << std::endl;
+    }
+}
diff --git a/12_1.cpp b/12_1.cpp
@@ -0,0 +1,34 @@
+#include <iostream>
+
+using namespace std;
+class Base {
+    public:
+    Base() {};
+        virtual void iam() { cout << "Base\n"; }
+        void iam2() { cout << "Base-iam2\n"; }
+};
+class Derived1: public Base {
+    public:
+    Derived1() {};
+        virtual void iam() { cout << "Derived1\n"; }
+        void iam2() { cout << "Derived1-iam2\n"; }
+};
+
+class Derived2: public Base {
+    public:
+    Derived2() {};
+        virtual void iam() { cout << "Derived2\n"; }
+};
+
+int main()
+{
+    Derived1 *d1 = new Derived1;
+    Derived2 *d2; 
+    Base *b = d1;
+    b->iam() ;
+    d1->iam() ;
+    b->iam2() ;
+    d2 = static_cast <Derived2 *>(b);
+    if(d2) d2->iam() ;
+    b->iam() ;
+}
diff --git a/13_1.cpp b/13_1.cpp
@@ -0,0 +1,78 @@
+#include <iostream>
+
+using namespace std;
+
+template<class T> class List {
+    typedef struct Link {
+        Link *pre;
+        Link *suc;
+        T val;
+        Link(Link *p, Link *s, const T& v): pre(p), suc(s), val(v) {}
+    } Link;
+    Link *head;
+    Link *curr;
+public:
+    List(): head(NULL), curr(NULL) {}
+    ~List() { for(Link *p=head; p; p=p->suc) delete p; }
+    List(const T & t): head(new Link(NULL, NULL, t)), curr(head) {}
+    void add(T t) { Link *l = new Link(NULL, NULL, t); 
+                      if(curr==NULL) curr = l; 
+                      if(head == NULL) head = l;
+                      l->pre = curr; l->suc=NULL;
+                      curr->suc=l;
+                      curr = l; }
+    Link *begin() { return head; }
+    Link *end() { return curr; }
+    void erase(Link *l) { 
+        for(Link *p=head; p; p=p->suc) {
+            if((unsigned int)p == (unsigned int)l) {
+                p->suc->pre = p->pre;
+                p->pre->suc = p->suc;
+                p->pre = NULL; p->suc = NULL;
+                delete p;
+                return ;
+            }
+        }
+    }
+    void remove(T t) { 
+        for(Link *p=head; p; p=p->suc) {
+            if(p->val == t) {
+                print_ptrs();
+                p->suc->pre = p->pre;
+                p->pre->suc = p->suc;
+                if((unsigned int)p == (unsigned int)head) {
+                    head = p->suc;
+                }
+                if((unsigned int)p == (unsigned int)curr) {
+                    curr = p->pre;
+                }
+                p->pre = NULL; p->suc = NULL;
+                delete p;
+                return;
+            }
+        }
+    }
+    size_t size() {
+        size_t i=0;
+        for(Link *p=head; p; p=p->suc) i++;
+        return i;
+    }
+    void print_all() {
+        for(Link *p=head; p; p=p->suc) std::cout << p->val << std::endl;
+    }
+    void print_ptrs() {
+        for(Link *p=head; p; p=p->suc) std::cout << p << " " << p->pre << " " << p->suc << std::endl;
+    }
+};
+
+int main()
+{
+    List<int> l;
+    l.add(1);
+    l.add(1);
+    l.add(2);
+    l.add(3);
+    l.print_all();
+    l.remove(1);
+    l.print_all();
+}