there is a string like

```
0123456789
string a = "25 + 5.6 - (54 - (-61))"
a[0] = 2
a[1] = 5
2 =
3 = +
4 =
5 = 5
6 = .
7 = 6
8 =
9 = -
10 =
11 = (
12 = 5
13 = 4
..
```

how can i get these numbers(integers or doubles) ?

is there function that works like that or similar ?

or i will do it :

```
f( string, index)
f(a,0) which returns 25
f(a,5) which returns 5.6
f(a,12) which returns 54
f(a,18) which returns -61
```