9.2、9.3 指针和字符串、字符串操作库函数

青旅半醒 2022-05-19 06:50 145阅读 0赞

![70][]

#include<iostream>
    using namespace std;
    int main()
    {
    	char * p = "Please input your name:";//字符串常量的类型是char * 
    	//cout << p << endl;
    	printf(p);
    	char name[20];//字符数组的名字也是char * 类型
    	char * pName;
    	pName = name;
    	cin >> pName;
    	cout << "Your name is: " << pName << endl;
    	return 0;	
    }

![70 1][]

![70 2][]

> 这里注意用scanf读入字符数组时，前面不能加“&”符号，因为字符数组名就是个地址。

![70 3][]

![70 4][]

![70 5][]

![70 6][]

![70 7][]

#include<iostream>
    #include<cstring>
    using namespace std;
    int main()
    {
    	char s1[100] = "12345";
    	char s2[100] = "abcdefg";
    	char s3[100] = "ABCDE";
    	strncat(s1,s2,3);//将s2中的前三个字符连在s1后面 s1="12345abc"
    	cout << "1) " << s1 << endl;
    	strncpy(s1,s3,3);//将s3中的前3个字符复制给s1，3<5,不加上'\0'  s1="ABC45abc"
    	cout << "2) " << s1 << endl;
    	//cout << strncpy(s2,s3,5) << endl;//ABCDEfg
    	strncpy(s2,s3,6);//将s3中的前6个字符复制给s2, 6>5,加上'\0' s2="ABCDE";
    	cout << "3) " << s2 << endl;	
    	cout << "4) " << strncmp(s1,s3,3) << endl;//比较s1和s3的前三个字符，发现都是ABC，所以输出0
    	char * p = strchr(s1,'B');//字符‘B’在s1中第一次出现的位置，找的是指针
    	if(p)
    		cout << "5) " << p - s1 << "," << *p << endl;//5) 1,B 
    	else
    		cout << "5) Not found" << endl;
    	p = strstr(s1, "45a");//45a在s1中第一次出现的位置
    	if(p)
    		cout << "6) " << p - s1 << "," << p << endl;//6) 3,45abc
    	else
    		cout << "6) Not found" << endl;
    	cout << "Strtok usage demo:" << endl;
    	char str[] ="- This, a sample string, OK.";
    	p = strtok(str," -,.");//当出现空格、逗号、句号、横杠时分隔单词
    	while(p != NULL)
    	{
    		cout << p << endl;
    		p = strtok(NULL," -,.");//后续调用，第一个必须为NULL 
    	}	 
    	return 0; 	 
    }

![70 8][]

[70]: /images/20220519/d391eeb63db94169b025cac73c6c1e33.png
[70 1]: /images/20220519/1a3297decd384571a23cdc627465e04a.png
[70 2]: /images/20220519/51061e84943442abbb494a01eb3550f3.png
[70 3]: /images/20220519/ae2dccad9e0f40e586745fe071ef167c.png
[70 4]: /images/20220519/6248a84678f4457e8ca38acaa23e675f.png
[70 5]: /images/20220519/7a7a94f2b8214945b8c017cd4e193f1a.png
[70 6]: /images/20220519/d1d80c6f42164581ad8f10f8009a09b3.png
[70 7]: /images/20220519/6dc47ffa3f7f4902a0e709507527837e.png
[70 8]: /images/20220519/bf838bd265264a29a0a5f72fc9ad48c5.png