3 replies to this topic

[Hamed]

Hello,
How can I convert math an string to math function for example
f(x)=cos(x)+sin(x)+x^2+x^1
and also log(x) ???

[dargueta]

Let me get this straight - you want to take a string as input and evaluate it to some floating-point number? If that's the case, you're going to need to use regular expressions and string parsing. If you have no experience with that, I suggest you find some alternative method.

[Alexander]

Do you mean something like this?

#include <stdio.h>
#include <math.h>

double f1(double);

int main(void) {
    printf("%lf", f1(2.43));
}

double f1(double x) {
    //cos(x)+sin(x)+x^2+x^1
    return
       cos(x) + sin(x) + pow(x, 2) + pow(x, 1);
}

If you do mean evaluating, tokenizing would be the way to go rather than language parsing (regular expression sets)

[Hamed]

I need very simple math expression parser.