[Solved] Expected identifier or ‘(‘

Question

I don’t quite see the point of another file under the same project just to print powers of three, but that’s possibly your homework.

Anyway, I think the whole point is to see how to include a file, so I also isolated the power function in another file.

power_calculator.c will accept two parameters, {number} and {power} respectively.

Here is how you can do it:

power_calculator.c

// power_calculator {n} {k}
// Calculates {n}^{k}
#include <stdio.h>
#include <stdlib.h>
// #include <math.h>
#include "math_power.h"

int main (int argc, char *argv[])
{
    // two parameters should be passed, n, and k respectively - argv[0] is the name of the program, and the following are params.
    if(argc < 3)
        return -1;
    // you should prefer using math.h's pow function - in that case, uncomment the #import <math.h>
    //printf("%f\n", power(atof(argv[1]), atof(argv[2])));

    // atof is used to convert the char* input to double
    printf("%f\n", math_power(atof(argv[1]), atof(argv[2])));

    return 0;
};

math_power.h

#ifndef _MATH_POWER_H_
#define _MATH_POWER_H_

double math_power(double number, double power);

#endif

math_power.c

#include "math_power.h"

double math_power(double number, double power){
    double result = 1;
    int i;

    for( i = 0; i < power; i++ ){
        result*=number;
    }

    return result;
}

powers_of_three.c

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

int main (int argc, char *argv[])
{
    int i;
    // here is your range 0-9
    for(i = 0; i < 10; i++)
        printf("%f\n", math_power(3, i));

    return 0;
};

To compile either powers_of_three.c or power_calculator.c, remember to include math_power.h and math_power.c.

Accepted Answer