C++精解【1】

hello,world

#include <iostream>using namespace std;int main()
{cout << "Hello world!" << endl;return 0;
}

getline

成员函数getline()是从输入流中读取一行字符，读到终止符时会将’\0’存入结果缓冲区中 [4]，作为输入的终止。终止符可以是默认的终止符，也可以是定义的终止符。函数的语法结构是：
getline(<字符数组chs>，<读取字符的个数n>，<终止符>)

#include <iostream>using namespace std;int main()
{string name;string welcomeMessage;cout << "Hello world!" << endl;cin>>name;cout << "Hi!" <<name<< endl;getline(cin,welcomeMessage,'#');cout<<welcomeMessage<<endl;return 0;
}

Hello world!
lisi
Hi!lisi
you are good student!
#you are good student!Process returned 0 (0x0)   execution time : 11.410 s
Press any key to continue.

std::cin

可同时接收多个数据输入，每个数据用空格分隔！

Hello world!
name age
lisi 29
Hi!lisi 29Process returned 0 (0x0)   execution time : 3.817 s
Press any key to continue.

#include <iostream>using namespace std;int main()
{string name;int age;int temp;string welcomeMessage;cout << "Hello world!" << endl;cout<<"name age"<<endl;cin>>name>>age;cout << "Hi!" <<name<<" "<<age<<endl;return 0;
}

引用与指针

• 标量

100
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88
99Process returned 0 (0x0)   execution time : 1.819 s
Press any key to continue.

#include <iostream>using namespace std;int main()
{int a;int &a1=a;int *a2=&a;cin>>a;cout<<a<<endl;a1=88;cout<<a<<endl;*a2=99;cout<<a<<endl;return 0;
}

• 数组指针

#include <iostream>using namespace std;int main()
{int a[]{1,2,3,4,5,6,7,8};int *s=a;for (int *p=a;p<s+8;p++){cout<<p<<":"<<*p<<endl;}
}

#include <iostream>using namespace std;int main()
{int a[]{1,2,3,4,5,6,7,8};for (int *p=a;p<a+8;p++){cout<<p<<":"<<*p<<endl;}
}

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8Process returned 0 (0x0)   execution time : 0.126 s
Press any key to continue.

• 数组的引用
  下面的程序是错误的

#include <iostream>using namespace std;int main()
{int a[]{1,2,3,4,5,6,7,8};for (int (&p)[8]=a;p<a+7;p++){cout<<*p<<endl;}}

错误如下

正确的写法只能如下：

#include <iostream>using namespace std;int main()
{int a[]{1,2,3,4,5,6,7,8};int (&p)[8]=a;for (int i=0;i<8;i++){cout<<p[i]<<endl;}
}

如果一定要用指针，只能考虑另外使用一个指针变量了，因为引用指向的内容可以更改，但引用本身的指向是不能更改，只读的。

#include <iostream>using namespace std;int main()
{int a[]{1,2,3,4,5,6,7,8};int (&p)[8]=a;for (int *p1=p;p1<a+8;p1++){cout<<*p1<<endl;}
}

函数

#include <iostream>using namespace std;void goThrough(int (&arr)[8]){for (int *p1=arr;p1<arr+8;p1++){cout<<*p1<<endl;}
}
int main()
{int a[]{1,2,3,4,5,6,7,8};goThrough(a);
}

更改数组元素

#include <iostream>using namespace std;void goThrough(int (&arr)[8]){for (int *p1=arr;p1<arr+8;p1++){cout<<*p1<<endl;}for (int *p1=arr;p1<arr+8;p1++){*p1*=10;}for (int *p1=arr;p1<arr+8;p1++){cout<<*p1<<endl;}
}
int main()
{int a[]{1,2,3,4,5,6,7,8};goThrough(a);
}

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80Process returned 0 (0x0)   execution time : 0.130 s
Press any key to continue.

参考文献

1、learn.microsoft.com
2、百度百科之geline