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techkangtechkang
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Update 重要.cpp
Implement some api which not implemented.
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  • practical_exercises/10_day_practice/day7/综合例题

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‎practical_exercises/10_day_practice/day7/综合例题/重要.cpp

Lines changed: 78 additions & 57 deletions
Original file line numberDiff line numberDiff line change
@@ -1,70 +1,91 @@
1-
//设计一个字符串类String，通过运算符重载实现字符串的输入、输出以及+=、==、!=、<、>、>=、[ ]等运算。
1+
//设计一个字符串类String，通过运算符重载实现字符串的输入、输出以及+=、==、!=、<、>、>=、[ ]等运算。
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#include <iostream>
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#include <cstring>
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using namespace std;
5-
class String {
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class String
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{
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private:
7-
int length; //字符串长度
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char *sPtr; //存放字符串的指针
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void setString( const char *s2);
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friend ostream &operator<<(ostream &os, const String &s);
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friend istream &operator>>(istream &is, String &s); //重载输入运算符
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int length; //字符串长度
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char *sPtr; //存放字符串的指针
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void setString(const char *s2);
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friend ostream &operator<<(ostream &os, const String &s)
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{
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return os << s.sPtr;
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};
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friend istream &operator>>(istream &is, String &s)
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{
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return is >> s.sPtr;
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}; //重载输入运算符
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public:
13-
String( const char * = "" );
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const String &operator=(const String &R); //重载赋值运算符 =
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const String &operator+=(const String &R); //字符串的连接 +=
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bool operator==(const String &R); //字符串的相等比较 ==
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bool operator!=(const String &R); //字符串的不等比较 !=
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bool operator!() ; //判定字符串是否为空
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bool operator<(const String &R) const; //字符串的小于比较 <
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bool operator>(const String &R); //字符串的大于比较 >
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bool operator>=(const String &R); //字符串的大于等于比较
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char &operator[](int); //字符串的下标运算
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~String();
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String(const char * = "");
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const String &operator=(const String &R)
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{
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length = R.length;
24+
strcpy(R.sPtr, sPtr);
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return *this;
26+
}; //重载赋值运算符 =
27+
const String &operator+=(const String &R); //字符串的连接 +=
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bool operator==(const String &R); //字符串的相等比较 ==
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bool operator!=(const String &R); //字符串的不等比较 !=
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bool operator!(); //判定字符串是否为空
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bool operator<(const String &R) const; //字符串的小于比较 <
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bool operator>(const String &R); //字符串的大于比较 >
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bool operator>=(const String &R); //字符串的大于等于比较
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char &operator[](int); //字符串的下标运算
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~String(){};
2436
};
25-
const String &String::operator+=(const String &R) {
26-
char *temp = sPtr;
27-
length += R.length;
28-
sPtr = new char[length+1];
29-
strcpy(sPtr,temp );
30-
strcat(sPtr,R.sPtr );
31-
delete [] temp;
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return *this;
37+
const String &String::operator+=(const String &R)
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{
39+
char *temp = sPtr;
40+
length += R.length;
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sPtr = new char[length + 1];
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strcpy(sPtr, temp);
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strcat(sPtr, R.sPtr);
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delete[] temp;
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return *this;
3346
}
34-
bool String::operator==(const String &R){return strcmp(sPtr,R.sPtr)==0;}
35-
bool String::operator!=(const String & R){return !(*this==R);}
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bool String::operator!(){return length ==0;}
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bool String::operator<(const String &R)const{return strcmp(sPtr,R.sPtr)<0;}
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bool String::operator>(const String &R){return R<*this;}
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bool String::operator>=(const String &R){return !(*this<R);}
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char &String::operator[](int subscript){return sPtr[subscript];}
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int main(){
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String s1("happy"),s2("new year"),s3;
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cout << "s1 is " << s1 << "\ns2 is " << s2 << "\ns3 is " << s3
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<< "\n比较s2和s1:"
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<< "\ns2 ==s1结果是 " << ( s2 == s1 ? "true" : "false")
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<< "\ns2 != s1结果是 " << ( s2 != s1 ? "true" : "false")
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<< "\ns2 > s1结果是 " << ( s2 > s1 ? "true" : "false")
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<< "\ns2 < s1结果是 " << ( s2 < s1 ? "true" : "false")
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<< "\ns2 >= s1结果是 " << ( s2 >= s1 ? "true" : "false");
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cout << "\n\n测试s3是否为空: ";
51-
if (!s3){
52-
cout << "s3是空串"<<endl; //L3
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cout<<"把s1赋给s3的结果是：";
54-
s3 = s1;
55-
cout << "s3=" << s3 << "\n"; //L5
47+
String::String(const char *str)
48+
{
49+
sPtr = new char[strlen(str) + 1];
50+
strcpy(sPtr, str);
51+
length = strlen(str);
52+
};
53+
bool String::operator==(const String &R) { return strcmp(sPtr, R.sPtr) == 0; }
54+
bool String::operator!=(const String &R) { return !(*this == R); }
55+
bool String::operator!() { return length == 0; }
56+
bool String::operator<(const String &R) const { return strcmp(sPtr, R.sPtr) < 0; }
57+
bool String::operator>(const String &R) { return R < *this; }
58+
bool String::operator>=(const String &R) { return !(*this < R); }
59+
char &String::operator[](int subscript) { return sPtr[subscript]; }
60+
int main()
61+
{
62+
String s1("happy"), s2("new year"), s3;
63+
cout << "s1 is " << s1 << "\ns2 is " << s2 << "\ns3 is " << s3
64+
<< "\n比较s2和s1:"
65+
<< "\ns2 ==s1结果是 " << (s2 == s1 ? "true" : "false")
66+
<< "\ns2 != s1结果是 " << (s2 != s1 ? "true" : "false")
67+
<< "\ns2 > s1结果是 " << (s2 > s1 ? "true" : "false")
68+
<< "\ns2 < s1结果是 " << (s2 < s1 ? "true" : "false")
69+
<< "\ns2 >= s1结果是 " << (s2 >= s1 ? "true" : "false");
70+
cout << "\n\n测试s3是否为空: ";
71+
if (!s3)
72+
{
73+
cout << "s3是空串" << endl; //L3
74+
cout << "把s1赋给s3的结果是：";
75+
s3 = s1;
76+
cout << "s3=" << s3 << "\n"; //L5
5677
}
57-
cout << "s1 += s2 的结果是：s1="; //L6
58-
s1 += s2;
59-
cout << s1; //L7
60-
61-
cout << "\ns1 += to you 的结果是："; //L8
62-
s1 += " to you";
63-
cout << "s1 = " << s1 <<endl; //L9
64-
s1[0] = 'H';
78+
cout << "s1 += s2 的结果是：s1="; //L6
79+
s1 += s2;
80+
cout << s1; //L7
81+
82+
cout << "\ns1 += to you 的结果是："; //L8
83+
s1 += " to you";
84+
cout << "s1 = " << s1 << endl; //L9
85+
s1[0] = 'H';
6586
s1[6] = 'N';
6687
s1[10] = 'Y';
67-
cout << "s1 = " << s1 << "\n"; //L10
88+
cout << "s1 = " << s1 << "\n"; //L10
6889
system("pause");
6990
return 0;
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}

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