C/C++中peek函数的原理及应用

 1 /* istream peek */
 2 #include <iostream>
 3 using namespace std;
 4 int main () 
 5 {
 6     char c;
 7     int n;
 8     char str[256];
 9     cout << "Enter a number or a word: ";
10     c=cin.peek();
11     if ( (c >= '0') && (c <= '9') )
12     {
13         cin >> n;
14         cout << "You have entered number " << n << endl;
15     }
16     else
17     {
18         cin >> str;
19         cout << " You have entered word " << str << endl;
20     }
21     return 0;
22 }

 1 char peek_char;
 2 
 3 static char peek()
 4 {
 5     return peek_char;
 6 }
 7 
 8 static void * __Peek_loop_func(void *pInputArg)
 9 {
10     char tmp_char;
11     while(1)
12     {
13         if(tmp_char=getchar())
14         {            
15             if((tmp_char!='\r')&&(tmp_char!='\n')&&(tmp_char!=0x0a))
16             {
17                 peek_char=tmp_char;
18                 printf("Input Char === [%c] \n",peek_char);    
19 
20                 if(peek_char=='q')
21                 {
22                     printf("Jmp out from serial == 2 \n");
23                     exit(1);
24                 }
25             }
26         }
27         usleep(1000*10);
28     }
29 }
30 
31 // 下面的代码放在主程序中，用来创建检测输入的线程.
32 
33 pthread_t tPeekThreadHandle;
34 pthread_create(&tPeekThreadHandle, NULL, &__Peek_loop_func, NULL);