Thread: Functions are killing me, help!

I have been trying to figure out the proper use of functions. I sort of understand them, but then again, I sort of don't. I know my calling of them in main is just a disaster, and as simple as this program sounds, it is really frustrating me.

I'd appreciate any help.

The purpose: takes two inputs from the user (voltage and resistance) in a function and returns the amp value (voltage / resistance *1000) and then prints it in main. There is also error checking that needs to be done to make sure the input values are greater than zero. Ugh.

Code:

#include <stdio.h>

float input(float volts, float resistance);
float current(float value);
void display(void);

float input(float volts, float resistance)
{
        float value, volts, resist;
        printf("Enter a value for voltage and resistance, separated by a space: ");
        scanf("%f %f", &volts, &resist);
        value = (volts/resist);
        return value;
}

float current(float value)
{
        float current;
        current=value*1000;
        return current;
}

void display(void)
{
        printf("The current is %f", current);
}

int main(void)
{
        float current;
        curent=current(value);
        display();
        return 0;

}
~

I am sure I have wrong floats being used and saved into functions..right now I feel as if I have absolutely no clue what I am doing. It sounded so simple when I read it a few days ago, but now =(

float current
and current(int)
ambiguous..the compiler will freak out

and no value variable declared..

Code:

float current(float value)
{
        float current;
        current=value*1000;
        return current;
}

is also incorrect...let the names be unique and it should be grand