练习1-9

 1 #include<stdio.h>
 2 int main()
 3 {
 4     int c, lastc;
 5     lastc = 0;
 6     while ((c = getchar()) != EOF)
 7     {
 8         if (c != ‘ ‘)
 9         {
10             putchar(c);
11         }
12         else if (lastc != ‘ ‘)
13         {
14             putchar(c);
15         }
16         lastc = c;
17     }
18     return 0;
19 }