2.11BSD/share/learn/C/L5.1g

#print
Write a program to copy its input to its output,
replacing each string of one or more blanks by
a single blank.
#once #create Ref
   This    has   lines   with several     blanks    
including some in  funny places.    
#once #create Ref1
          
#once #create Answer
 This has lines with several blanks 
including some in funny places. 
 
#user
a.out <Ref >test
a.out <Ref1 >>test
#cmp test Answer
#succeed
One way:

 #include <stdio.h>

main()
{
	int c;

	for (c = getchar(); c != EOF; ) {
		putchar(c);
		if (c == ' ')
			while ((c = getchar()) == ' ')
				;
		else
			c = getchar();
	}
}
#log
#next
9.1a 10