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How to get and evaluate expressions from a string in C

How to get and evaluate expressions from a string in C

char *str = "2*8-5+6";

This should give a score of 17 after being evaluated.

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Try it yourself. you can use the stack data structure to evaluate this string here, this is the implementation reference (its in C ++) stack data structure for string computation



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You have to do it yourself, C provides no way to do this. C is a very low level language. The easiest way to do this is to find a library that does it, or if that doesn't exist, use lex + yacc to create your own interpreter.

A quick google suggests the following:



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You should try TinyExpr . This is one C source code (no dependencies) that you can add to your project.

Using this solution to solve your problem is simple:

#include <stdio.h>    
#include "tinyexpr.h"

int main()
{
    double result = te_interp("2*8-5+6", 0);
    printf("Result: %f\n", result);
    return 0;
}

This will print: Result: 17

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