What am I doing wrong?

[Hobox]

I wasn't aware you could "print" a backspace which seems useful and cool to know, so thanks for kind of teaching me that. 

 

Now, for the program. It's actually far easier to iterate over strings in C using a pointer, since they are just arrays of characters.

 

#include <stdio.h>

int main(void) {
	
	char str[] = "These have one space between. These  have  two  spaces  between.\n";
	char* ptr = str;
	int count = 0;
	
	printf("Before:\t%sAfter:\t", str);
	
	while (*ptr) {
		
		printf("%c", *ptr);
	    if (*ptr == ' ') {
	    	
	        count++;
	        if (count == 2) {
	        	
	            count -= 2;
	            printf("\b");
	        }
	    }
	    else if (count > 0) {
	    	count--;
	    }
	    
	    ptr++;
	}

	return 0;
}

 

Here's a working version of the program.

 

You start the pointer at the beginning of the string and just increment its value by 1 each iteration of the while loop. When you find a space, you increment a counter. When the counter equals 2, you set it back to zero and backspace a character. However, you have to remember that if the character isn't a space and the previous one was a space (so when count==1 and *ptr!=' ' you have to set the counter back to zero.