C++

Forum

 
 
Finding white space, new lines and dashes

lunafly (10)
I am struggling with getting my function to find either a space, new line, or dash ( - ) in my string. I was able to write it to find a space with no problem, but when I try to add a new line (\n) or a dash (-) to the search parameters, it doesn't work. I am basically writing two functions: one to find the length of a word, and one to find the beginning of a word. These are both used later as a part of a more complex function. What I have that works:

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
 
//start of word function
int word_start(int start, string paragraph)
{
	int now_start;
	now_start= paragraph.find_first_not_of(" ", start);
	
	return now_start;
}

//length of word function
int word_length(int start, string paragraph)
{
	int length;
	int end;
	end= paragraph.find(" ", start);
	
	if(end==-1)
	{
		end= paragraph.find_last_not_of(" ");
		length= end - start +1;
	}
	else
		length= end- start;
	return length;
}


When I try to change it to search for dashes and new lines, I write:
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
 
//start of word function
int word_start(int start, string paragraph)
{
	int now_start;
	now_start= paragraph.find_first_not_of("- \n", start);
	
	return now_start;
}

//length of word function
int word_length(int start, string paragraph)
{
	int length;
	int end;
	end= paragraph.find("- \n", start);
	
	if(end==-1)
	{
		end= paragraph.find_last_not_of("- \n");
		length= end - start +1;
	}
	else
		length= end- start;
	return length;
}


This doesn't work. I definitely feel this is a syntax error; however I haven't been able to figure out how to write this correctly. All the examples I have found say that when searching for multiple characters to write them all mashed together like

 
 
paragraph.find_last_not_of("aeiou")


which I have been trying to replicate with " ", - and \n but with no success. Any insight would be most appreciated!!
lunafly (10)
I figured it out! To find one of two (or several) different characters, you need to use the find_first_of function, not the find function! Using find searches for the exact phrase within the quotes, while the find_first_of function searches for the first character that matches any of the ones specified in the quotes.

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
 
//start of word function
int word_start(int start, string paragraph)
{
	int now_start;
	now_start= paragraph.find_first_not_of("- ", start);
	
	return now_start;
}

//length of word function
int word_length(int start, string paragraph)
{
	int length;
	int end;
	end= paragraph.find_first_of(" -", start);
	
	if(end==-1)
	{
		end= paragraph.find_last_not_of("- ");
		length= end - start +1;
	}
	else
		length= end- start;
	return length;
}
Topic archived. No new replies allowed.