当前位置：网站首页>I/O stream summary

I/O stream summary

2022-08-04 14:37:00 【51CTO】

I don't know the exact situation yet,There is a vague understanding,It will be updated continuously in the future

输入流：It's the equivalent of poking a hose into the program,Everything you type is put into the pipe in turn,<<Equivalent to you putting something in a pipe

输出流：This is another hose that pokes into the program,Everything he has calculated is put here,>>Equivalent to you taking something from a water pipe

举个例子

cin>>a>>b;

Equivalent to you putting one in the streama,一个空格,一个b,一个回车;

       
       #include <iostream>
       
       #include <cstdio>
       
       typedef 
       
       long 
       
       long 
       
       ll;
       
       using 
       
       namespace 
       
       std;
       
       int 
       
       main()
       
{
       
       int 
       
       a,
       
       b;
       
       char 
       
       c,
       
       f;
       
       cin
       
       >>
       
       a
       
       >>
       
       b;
       
       c 
       
       = 
       
       getchar();
       
       //getchar()The effect is to get a character in the stream
       
       if(
       
       c 
       
       == 
       
       ' ')
       
    {
       
       printf(
       
       "空格\n");
       
    }
       
       if(
       
       c 
       
       == 
       
       '\n')
       
    {
       
       printf(
       
       "回车\n");
       
    }
       
       scanf(
       
       "%c",
       
       &
       
       f);
       
       printf(
       
       "%c\n",
       
       f);
       
       return 
       
       0;
       
}
      
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.
19.
20.
21.
22.
23.
24.

程序的执行结果是：

输入输出流总结_ios

One might ask where the whitespace in the stream went？

getchar()The function of the function is to read a string from the keyboard,并带回显,getchar()The function waits for input until exit is pressed,All entered characters before the carriage return are displayed one by one on the screen,但只有第一个字符作为函数的返回值.

读入2The spaces in the middle of the numbers are automatically filtered by the system,Otherwise, the system would not be so stupid

如果你输入1空格2空格回车,spaces will be output,The first space was skipped by the system,The second space will not be skipped by the system

       
       #include <iostream>
       
       #include <cstdio>
       
       typedef 
       
       long 
       
       long 
       
       ll;
       
       using 
       
       namespace 
       
       std;
       
       int 
       
       main()
       
{
       
       char 
       
       a,
       
       b;
       
       a 
       
       = 
       
       getchar();
       
       printf(
       
       "%c\n",
       
       a);
       
       scanf(
       
       "%c",
       
       &
       
       b);
       
       printf(
       
       "%c\n",
       
       b);
       
       return 
       
       0;
       
}
      
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.

程序的运行结果是：

输入输出流总结_输出流_02

刚开始输入456,4被getchar()读了,The remaining characters are left in the stream,When the program reads it again, the stream is left behind5给读出来了

scanf和cin结束的'\n'stay in the flow,If encountered, it can be read'\n'的函数,These functions will read in'\n'结束,Nothing else will be entered,能读入'\n'的函数有getchar(),gets(),cin.getline(),

       
       #include <iostream>
       
       #include <cstdio>
       
       typedef 
       
       long 
       
       long 
       
       ll;
       
       using 
       
       namespace 
       
       std;
       
       char 
       
       b[
       
       10];
       
       int 
       
       main()
       
{
       
       char 
       
       a;
       
       cin
       
       >>
       
       a;
       
       gets(
       
       b);
       
       cout
       
       <<
       
       b
       
       <<
       
       endl;;
       
       cout
       
       <<
       
       "end"
       
       <<
       
       endl;
       
}
      
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.

程序的运行结果是：

输入输出流总结_ios_03

只输入一个4程序就跑完了,gets()读入的是'\n'

最后总结一下吧,If you just started typing a alphanumeric or something,后面又有一个gets()之类的函数,It should be in the stream'\n'If you eat it, it will be eaten by the next one, which will cause an error,If the following input function will not read in'\n'Then he will'\n'automatically discarded,这个'\n'It doesn't matter if you eat it or not

       
       #include <iostream>
       
       #include <cstdio>
       
       typedef 
       
       long 
       
       long 
       
       ll;
       
       using 
       
       namespace 
       
       std;
       
       char 
       
       b[
       
       10];
       
       int 
       
       main()
       
{
       
       char 
       
       a;
       
       cin
       
       >>
       
       a;
       
       cin
       
       >>
       
       b;
       
       getchar();
       
       gets(
       
       b);
       
       cout
       
       <<
       
       b
       
       <<
       
       endl;;
       
       cout
       
       <<
       
       "end"
       
       <<
       
       endl;
       
}
      
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
16.
17.
18.