文章目录

  • ​​cin读取空格前字符串​​
  • ​​以\0结尾​​
  • ​​cin.get()读取一行​​
  • ​​sizeof()和strlen()​​
  • ​​strcat()和strncat()：字符串的合并​​
  • ​​strcpy()和strncpy()：字符串拷贝​​
  • ​​memmove()：字符串拷贝​​
  • ​​参考博客​​

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