[C++知识库]C++中char型字符串

cin读取空格前字符串

# include<iostream>
using namespace std;

int main()
{
	 char a[20];
	 cin >> a;
	 cout << "输入的是：" << a << endl;
	 cout << "sizeof(a)：" << sizeof(a) << endl; 
	
	 return 0;
}

aaa 111
输入的是：aaa
sizeof(a)：20

总结：读到空格便结束

以\0结尾

# include<iostream>
using namespace std;

int main()
{
	 char a[20];
	 cin >> a;
	 
	 cout << "输入的是：";
	 for(int i = 0; a[i] != '\0'; i++){
	 	cout << a[i];
	 }
	 cout << endl;
	
	 return 0;
}

sad 222
输入的是：sad

cin.get()读取一行

# include<iostream>
using namespace std;

int main()
{
	 char a[20];	
	 cin.get(a, 20);
	
	 cout << "输入的是：" << a << endl;
	
	 return 0;

}

aaa 111
输入的是：aaa 111

# include<iostream>
using namespace std;

int main()
{
   char a[]={'a', 32, 'b', 65, ' ', 'B', '\0'};

   cout << a << endl;
   cout << "sizeof(a)：" << sizeof(a) << endl; 

   return 0;
}

a bA B
sizeof(a)：7

sizeof()和strlen()

# include<iostream>
using namespace std;
#include<bits/stdc++.h>

int main()
{
	char a[12] = {"Hello World"};
	cout << "a:" << a << endl;
	
	cout << "strlen(a):" << strlen(a) << endl;
	cout << "sizeof(a):" << sizeof(a) << endl << endl;
	
	
	a[5]='\0';
	cout <<  "a:" << a << endl;
	cout << "strlen(a):" << strlen(a) << endl;
	cout << "sizeof(a):" << sizeof(a) << endl;
	
	return 0;
}

a:Hello World
strlen(a):11
sizeof(a):12

a:Hello
strlen(a):5
sizeof(a):12

总结：

• strlen 输出的是可见字符的长度，遇到’\0’就结束了；
• sizeof 输出的是所有字符的长度，’\0’不结束，也算作是一个字符；
  
  
  

strcat()和strncat()：字符串的合并

strcat()：将ch2全部合并到ch1上

#include<iostream>
using namespace std;
#include<string.h>

int main()
{   
	char ch1[50] = {"What is your name?"};
	char ch2[] = {"My name is Mike!"};
	
	strcat(ch1, ch2);
	
	//strcat表示ch2中的字符串复制到ch1中，ch1中我们必须保证ch1能够容纳ch1和ch2的所有字符串，否则会产生错误
	cout << "ch1：" << ch1 << endl;
	cout << "ch2：" << ch2 << endl;
	
	return 0;
}

ch1：What is your name?My name is Mike!
ch2：My name is Mike!

strncat()：将ch2的部分合并到ch1上

#include<iostream>
#include<string.h> 
using namespace std;

int main()
{   
	char ch1[10] = {"12"};
	char ch2[] = {"abcdef"};
	
	strncat(ch1, ch2, 3);
	//3代表需要复制的ch2中的字符串的个数
	
	cout << "ch1：" << ch1 << endl;
	cout << "ch2：" << ch2 << endl;
	
	return 0;
}

ch1：12abc
ch2：abcdef

strcpy()和strncpy()：字符串拷贝

strcpy()：将ch2拷贝到ch1上，抹去ch1原来的数据

#include<iostream>
#include<string.h> 
using namespace std;

int main()
{   
	char ch1[10] = {"11222222"};
	char ch2[] = {"abcdef"};
	
	strcpy(ch1, ch2);

	cout << "ch1：" << ch1 << endl;
	cout << "ch2：" << ch2 << endl;
	
	return 0;
}

ch1：abcdef
ch2：abcdef

strncpy()

#include<iostream>
#include<string.h> 
using namespace std;

int main()
{   
	char ch1[10] = {"11222222"};
	char ch2[] = {"abcdef"};
	
	//把ch2前5字符赋值给ch1相应位置 
	strncpy(ch1, ch2, 5);

	cout << "ch1：" << ch1 << endl;
	cout << "ch2：" << ch2 << endl;
	
	return 0;
}

ch1：abcde222
ch2：abcdef

memmove()：字符串拷贝

#include<iostream>
#include<string.h> 
using namespace std;

int main()
{   
	char ch1[15] = {"abcdefghijklmn"};
	char ch2[] = {"1234567890"};
	cout<<"原ch1字符串："<<ch1<<endl;
	
	memmove(ch1, ch2, 10);
	//字符串替换 
	
	cout << "拷贝后ch1：" << ch1 << endl;
	return 0;
}

原ch1字符串：abcdefghijklmn
拷贝后ch1：1234567890klmn

参考博客

C++char型字符串：https://blog.csdn.net/CYKsky/article/details/42065385
C语言的字符串的操作函数：https://blog.csdn.net/wuyuzun/article/details/82117136
https://blog.csdn.net/weixin_46562430/article/details/120385042