1.全面的MyString
输出：
1. abcd-efgh-abcd-
2. abcd-
3.
4. abcd-efgh-
5. efgh-
6. c
7. abcd-
8. ijAl-
9. ijAl-mnop
10. qrst-abcd-
11. abcd-qrst-abcd- uvw xyz
about
big
me
take
abcd
qrst-abcd-
1 /*使程序输出指定结果*/
2 #include <cstdlib>
3 #include <iostream>
4 using namespace std;
5 int strlen(const char * s)
6 { int i = 0;
7 for(; s[i]; ++i);
8 return i;
9 }
10
11 void strcpy(char * d,const char * s)
12 {
13 int i = 0;
14 for( i = 0; s[i]; ++i)
15 d[i] = s[i];
16 d[i] = 0;
17
18 }
19
20 int strcmp(const char * s1,const char * s2)
21 {
22 for(int i = 0; s1[i] && s2[i] ; ++i) {
23 if( s1[i] < s2[i] )
24 return -1;
25 else if( s1[i] > s2[i])
26 return 1;
27 }
28 return 0;
29 }
30
31 void strcat(char * d,const char * s)
32 {
33 int len = strlen(d);
34 strcpy(d+len,s);
35 }
36
37 class MyString
38 {
39 // 在此处补充你的代码
40 char *p;
41 public:
42 MyString(const char * s = NULL) { //擅于利用缺省的参数，不要再写一个
43 if(s) {
44 p = new char[strlen(s) + 1];
45 strcpy(p,s);
46 }
47 else
48 p = NULL;
49
50 }
51 ~MyString() { if(p) delete [] p; }
52 MyString(const MyString & s){
53 if(s.p==NULL) p = NULL;
54 else{
55 p = new char[strlen(s.p) + 1];
56 strcpy(p,s.p);
57 }
58 }
59 MyString & operator=(const MyString & s) {
60 if(p) delete [] p;
61 if(s.p==NULL){
62 p = NULL; return * this;
63 }
64 p = new char[strlen(s.p)+1];
65 strcpy(p, s.p);
66 return * this;
67 }
68 MyString & operator=(const char * s) {
69 if(p) delete [] p;
70 if(s==NULL){
71 p = NULL; return * this;
72 }
73 p = new char[strlen(s)+1];
74 strcpy(p, s);
75 return * this;
76 }
77 char & operator[](const int i){
78 return p[i];
79 }
80 friend MyString operator+(const MyString & a, const MyString & b){
81 MyString ans;
82 ans.p = new char[strlen(a.p)+strlen(b.p)+1];
83 strcpy(ans.p, a.p);
84 strcat(ans.p, b.p); //不能改变原来的a
85 return ans;
86 }
87 MyString & operator+=(const char * s) {
88 MyString temp(s);
89 *this = *this+temp;
90 return * this;
91 }
92 bool operator<(const MyString s){
93 return (strcmp(p, s.p)==-1);
94 }
95 bool operator>(const MyString s){
96 return (strcmp(p, s.p)==1);
97 }
98 bool operator==(const MyString s){
99 return (strcmp(p, s.p)==0);
100 }
101 char * operator()(int start, int len){
102 char *temp = new char[len+1];
103 for (int i = start; i < start+len; i++){
104 temp[i-start] = p[i];
105 }
106 temp[len] = '\0';
107 return temp;
108 }
109 friend ostream & operator<<(ostream & o, const MyString & s){
110 if(s.p==NULL )return o; // 空指针就不输出了
111 o<<s.p;
112 return o;
113 }
114
115 };
116
117
118 int CompareString( const void * e1, const void * e2)
119 {
120 MyString * s1 = (MyString * ) e1;
121 MyString * s2 = (MyString * ) e2;
122 if( * s1 < *s2 ) //重载小于号
123 return -1;
124 else if( *s1 == *s2)
125 return 0;
126 else if( *s1 > *s2 ) //重载大于号
127 return 1;
128 }
129
130 int main()
131 {
132 MyString s1("abcd-"),s2,s3("efgh-"),s4(s1); //构造函数、复制构造函数
133 MyString SArray[4] = {"big","me","about","take"};
134 cout << "1. " <<s1<<s2<<s3<< s4<< endl; //重载流插入 不能读 空指针
135 s4 = s3; //重载等于号
136 s3 = s1 + s3; // 重载+号
137 cout << "2. " << s1 << endl;
138 cout << "3. " << s2 << endl;
139 cout << "4. " << s3 << endl;
140 cout << "5. " << s4 << endl;
141 cout << "6. " << s1[2] << endl;
142 s2 = s1;
143 s1 = "ijkl-"; //重载等于号
144 s1[2] = 'A' ; // 重载中括号
145 cout << "7. " << s2 << endl;
146 cout << "8. " << s1 << endl;
147 s1 += "mnop"; //重载+=
148 cout << "9. " << s1 << endl;
149 s4 = "qrst-" + s2;
150 cout << "10. " << s4 << endl;
151 s1 = s2 + s4 + " uvw " + "xyz";
152 cout << "11. " << s1 << endl;
153 qsort(SArray,4,sizeof(MyString),CompareString);
154 for( int i = 0;i < 4;i ++ )
155 cout << SArray[i] << endl;
156 //s1的从下标0开始长度为4的子串
157 cout << s1(0,4) << endl; //重载小括号
158 //s1的从下标5开始长度为10的子串
159 cout << s1(5,10) << endl;
160 return 0;
161 }
备注：这道题应该就是为了第二道题做铺垫，让我们感受一下继承的便捷。这道题的启发在于cout不能输出空指针！！！如果输出空指针，之后的输出就都输出不了了。
2.继承自string的MyString
1 #include <cstdlib>
2 #include <iostream>
3 #include <string>
4 #include <algorithm>
5 using namespace std;
6 class MyString:public string
7 {
8 // 在此处补充你的代码
9 public:
10 MyString(): string() {}
11 MyString(const string s): string(s){}
12 MyString(const char * s): string(s){}//为什么要写这一行
13 string operator()(int start, int len){
14 return substr(start, len);
15 }
16 };
17
18
19 int main()
20 {
21 MyString s1("abcd-"),s2,s3("efgh-"),s4(s1);
22 MyString s5 = "abds";
23 //MyString SArray[4] = {"big","me","about","take"};
24 cout << "1. " << s1 << s2 << s3<< s4<< endl;
25 s4 = s3;
26 s3 = s1 + s3;
27 cout << "2. " << s1 << endl;
28 cout << "3. " << s2 << endl;
29 cout << "4. " << s3 << endl;
30 cout << "5. " << s4 << endl;
31 cout << "6. " << s1[2] << endl;
32 s2 = s1;
33 // s1 = "ijkl-";
34 s1[2] = 'A' ;
35 cout << "7. " << s2 << endl;
36 cout << "8. " << s1 << endl;
37 s1 += "mnop";
38 cout << "9. " << s1 << endl;
39 s4 = "qrst-" + s2;
40 cout << "10. " << s4 << endl;
41 s1 = s2 + s4 + " uvw " + "xyz";
42 cout << "11. " << s1 << endl;
43 sort(SArray,SArray+4);
44 for( int i = 0;i < 4;i ++ )
45 cout << SArray[i] << endl;
46 //s1的从下标0开始长度为4的子串
47 cout << s1(0,4) << endl;
48 //s1的从下标5开始长度为10的子串
49 cout << s1(5,10) << endl;
50 return 0;
51 }
备注：注意标黄的一行，如果少了会编译报错。问了助教学长，答复是，做MyString a="xxx"的时候，实际上先把"xxx"变成了string，然后再变成MyString，需要两步隐式的类型转换，而这个是不支持的。
3.魔兽世界2
1 #include <iostream>
2 #include <string>
3 #include<cstdio>
4 #include<cstring>
5 using namespace std;
6 //武士一共有 dragon 、ninja、iceman、lion、wolf 五种。每种武士都有编号、生命值、攻击力这三种属性
7 //红方司令部按照iceman、lion、wolf、ninja、dragon的顺序循环制造武士。
8 //蓝方司令部按照lion、dragon、ninja、iceman、wolf的顺序循环制造武士。
9 //编程规范：变量名中间字母大写，类名、函数名首字母大写
10 //莫名其妙的问题看看循环的下标是不是写错了！
11 class Command; //复合关系
12
13 class Soldier{ //武士
14 private:
15 Command *com; //属于哪个司令部
16 int kind; //是哪种武士
17 int id; //编号
18 public:
19 Soldier(Command*p, int kindd, int idd);
20 void Print(int time);
21 static int life[5]; //生命值
22 static string weapon[3]; //新加武器
23 static string name[5]; //dragon 、ninja、iceman、lion、wolf
24 };
25
26 class Command{ //司令部
27 private:
28 Soldier *mySoldier[1000]; //都有哪些士兵
29 int HP; //总血量
30 int color; //蓝方为1, 红方为0
31 int sNum[5]; //存放每种士兵的数量
32 int curID; //当前制造到了第curID个士兵
33 int curkind; //当前制造的种类（用在该颜色的order里是第几个表示，即相对编号）
34 bool flag; //用来记录生命值用完了没有
35 public:
36 static int order[2][5]; //制造顺序
37 void Init(int col, int life);
38 bool Creat(int time);
39 ~Command();
40 friend class Soldier; //友元关系不可继承
41 friend class Dragon;
42 friend class Lion;
43 };
44
45 class Dragon: public Soldier{
46 string weap; //获得编号为n%3;
47 double morale; //降生后其司令部剩余生命元的数量除以造dragon所需的生命元数量
48 public:
49 Dragon(Command*p, int kindd, int idd):Soldier(p, kindd, idd),weap(weapon[idd%3]),morale(double(p->HP)/life[0]){}
50 void Printinfo(){
51 printf("It has a %s,and it's morale is %.2lf\n",weap.c_str(),morale);
52 }
53 };
54
55 class Ninja: public Soldier{
56 string weap1, weap2; //获得编号为 n%3 和 (n+1)%3的武器
57 public:
58 Ninja(Command*p, int kindd, int idd):Soldier(p, kindd, idd),weap1(weapon[idd%3]), weap2(weapon[(idd+1)%3]){}
59 void Printinfo(){
60 printf("It has a %s and a %s\n",weap1.c_str(), weap2.c_str());
61 }
62 };
63
64 class Iceman: public Soldier{
65 string weap;//获得编号为 n%3 的武器
66 public:
67 Iceman(Command*p, int kindd, int idd):Soldier(p, kindd, idd),weap(weapon[idd%3]){}
68 void Printinfo(){
69 printf("It has a %s\n",weap.c_str());
70 }
71 };
72
73 class Lion: public Soldier{
74 int loyalty; //它降生后其司令部剩余生命元的数目
75 public:
76 Lion(Command*p, int kindd, int idd):Soldier(p, kindd, idd),loyalty(p->HP){}
77 void Printinfo(){
78 printf("It's loyalty is %d\n", loyalty);
79 }
80 };
81
82 class Wolf: public Soldier{
83
84 };
85
86 string Soldier::name[5]={"dragon","ninja","iceman","lion","wolf"};
87 int Soldier::life[5];
88 string Soldier::weapon[3] = {"sword", "bomb", "arrow"};
89 int Command::order[2][5]={{2,3,4,1,0},{3,0,1,2,4}};
90
91 Soldier::Soldier(Command *p, int kindd, int idd){
92 com = p;
93 kind = kindd;
94 id = idd;
95 }
96
97 void Soldier::Print(int time){
98 char color[6];
99 if(com->color==1) strcpy(color, "blue"); //char字符串可以直接用=初始化，但不能这么赋值
100 else strcpy(color, "red");
101 printf("%03d %s %s %d born with strength %d,%d %s in %s headquarter\n",
102 time, color, name[kind].c_str(), id, life[kind], com->sNum[kind],name[kind].c_str(),color);
103 }
104
105 void Command::Init(int col, int life){ //初始化
106 color = col;
107 HP = life;
108 flag = false;
109 curID = 1;
110 curkind = 0;
111 memset(sNum, 0, sizeof(sNum));
112 }
113
114 //string Soldier::name[5]={"dragon","ninja","iceman","lion","wolf"};
115 bool Command::Creat(int time){
116 if(flag) return false; //已经不能再造了
117 int i, kind;
118 int orikind = curkind;
119 for(i = 0; i < 5; i++){
120 curkind = (orikind+i)%5; //这块不能写成curkind = (curkind+i)%5;！！！！！注意!!!!
121 kind = order[color][curkind]; //这里是绝对编号
122 if(Soldier::life[kind]<=HP) break;
123 }
124 if(i >= 5){ //已经轮完一轮了,并且这是第一次不能制造新兵
125 flag = true;
126 if(color) printf("%03d blue headquarter stops making warriors\n",time); //格式化输出
127 else printf("%03d red headquarter stops making warriors\n",time);
128 return false;
129 }
130 //成功制造士兵
131 mySoldier[curID]=new Dragon(this, kind, curID);
132 sNum[kind]++;
133 HP-=Soldier::life[kind];
134 mySoldier[curID]->Print(time);
135 switch(kind){ //case里不能定义局部变量，除非加作用域符号{}
136 case 0:
137 {Dragon d(this, kind, curID); d.Printinfo(); break;}
138 case 1:
139 {Ninja n(this, kind, curID); n.Printinfo(); break;}
140 case 2:
141 {Iceman ii(this, kind, curID); ii.Printinfo(); break;}
142 case 3:
143 {Lion l(this, kind, curID); l.Printinfo(); break;}
144 case 4: break;
145 }
146 //各种序号要+1
147 curkind = (curkind+1)%5;
148 curID++;
149 return true;
150 }
151
152 Command::~Command(){
153 for(int i=0;i<curID;i++)
154 delete mySoldier[i];
155 }
156
157 int main(){
158 int T, M;
159 Command Blue, Red;
160 scanf("%d", &T);
161 for(int i = 1; i <= T; i++){
162 printf("Case:%d\n",i);
163 scanf("%d",&M);
164 Blue.Init(1,M);
165 Red.Init(0,M);
166 for(int j = 0; j <= 4; j++)
167 scanf("%d", &Soldier::life[j]);
168 int time = 0;
169 while(1){
170 bool flagred = Red.Creat(time);
171 bool flagblue = Blue.Creat(time);
172 time++;
173 if(!flagred&&!flagblue) break;
174 }
175 }
176 return 0;
177 }
备注：我没啥好说的……看注释吧。我也不知道我这种写法好不好orz
来源：https://www.cnblogs.com/fangziyuan/p/12546796.html