C++ How is this not splitting my string using a delimeter?

[Velpus Captiosus]

I have this code:

#include <string.h>

void splitString(string query,char delimeter)
{
    int i,j=0;

                int end = query.size();

                while(i<end)
                {

                   j = query.find(delimeter,i);

                   cout << query.substr(i,j);



                    i = j;



               }
    
}

In my brain this splits a string.For example if we have the query string "Hello|World|" and the delimeter char 'I' we should get in the output : Hello World.Yet when I am running the program it doesnt!

 

[Malcolm]

Hey @Velpus Captiosus! I'll see if I can get you some help on this 🙂

@simong1993 @Antero360 @Johna @BorkedSystem32 any idea what may be causing this?

 

[Johna]

@Malcolm I haven't used C++ before, other than "Hello World" 4 years ago 😂.

@Velpus Captiosus What output are you getting? the same "Hello|World|"? or something else?

 

[Velpus Captiosus]

@Malcolm I haven't used C++ before, other than "Hello World" 4 years ago 😂.

@Velpus Captiosus What output are you getting? the same "Hello|World|"? or something else?

I dont get anything in the output.

 

[Johna]

Any errors?

 

[Velpus Captiosus]

Any errors?

No.

 

[Antero360]

I have this code:

#include <string.h>

void splitString(string query,char delimeter)
{
    int i,j=0;

                int end = query.size();

                while(i<end)
                {

                   j = query.find(delimeter,i);

                   cout << query.substr(i,j);



                    i = j;



               }
   
}

In my brain this splits a string.For example if we have the query string "Hello|World|" and the delimeter char 'I' we should get in the output : Hello World.Yet when I am running the program it doesnt!

Hi there,
I do believe you're missing a function declaration at the top like this

 

[Antero360]

Hi there,
I do believe you're missing a function declaration at the top like this

Also... might want to check your logic there before you run it lol... you're running into an infinite loop it looks like

 

[Velpus Captiosus]

Also... might want to check your logic there before you run it lol... you're running into an infinite loop it looks like

The loop ends when i>end.

 

[Johna]

The loop ends when i>end.

If I understood the code well, then i never gets more than 5 (end is 12) when using the string `Hello|World|".

Create a trace table, and this is what you get:

end​	i​	j​	Output​
12​	0​	0​
	5​	5​	Hello​
	5​	5​	|Worl​
	5​	5​	|Worl​

And that last row keeps on repeating.

 

[Velpus Captiosus]

If I understood the code well, then i never gets more than 5 (end is 12) when using the string `Hello|World|".

Create a trace table, and this is what you get:

end​	i​	j​	Output​
12​	0​	0​
	5​	5​	Hello​
	5​	5​	|Worl​
	5​	5​	|Worl​

And that last row keeps on repeating.

Why tho?

 

[Johna]

Added comments with line numbers to make it easier to explain.

/* 1*/ #include <string.h>
/* 2*/
/* 3*/ void splitString(string query,char delimeter)
/* 4*/ {
/* 5*/     int i,j=0;
/* 6*/     int end = query.size();
/* 7*/     while(i<end)
/* 8*/     {
/* 9*/         j = query.find(delimeter,i);
/*10*/         cout << query.substr(i,j);
/*11*/         i = j;
/*12*/     }
/*13*/ }

In line 9, j is set to 5, because the character is found in position 5 in the string.
In line 11, i is set to j, which is 5.

Back to line 7, 5 (i) is less than 12 (end), so the loop continues.
Line 9, you start searching from 5 (i), so the character is again found at position 5.
Line 11, i is again set to 5.

i is still 5, so still less than 12.
Loop continues infinitely.

 

[Velpus Captiosus]

Added comments with line numbers to make it easier to explain.

/* 1*/ #include <string.h>
/* 2*/
/* 3*/ void splitString(string query,char delimeter)
/* 4*/ {
/* 5*/     int i,j=0;
/* 6*/     int end = query.size();
/* 7*/     while(i<end)
/* 8*/     {
/* 9*/         j = query.find(delimeter,i);
/*10*/         cout << query.substr(i,j);
/*11*/         i = j;
/*12*/     }
/*13*/ }

In line 9, j is set to 5, because the character is found in position 5 in the string.
In line 11, i is set to j, which is 5.

Back to line 7, 5 (i) is less than 12 (end), so the loop continues.
Line 9, you start searching from 5 (i), so the character is again found at position 5.
Line 11, i is again set to 5.

i is still 5, so still less than 12.
Loop continues infinitely.

But the find() searches after a position.

 

[Johna]

But the find() searches after a position.

Yes, it searches from position 5, which is where the character you're looking for is.

Line 9, you start searching from 5 (i), so the character is again found at position 5.

 

[Antero360]

Yes, it searches from position 5, which is where the character you're looking for is.

should be i+1