Help with square root using pseudocode

[AFCKING]

#include "stdio.h"float squareRoot(float number, float accuracy);
int main()
{	
   
	float a;
        printf("\nsquare root test 1: enter a number\n");
        scanf("%f",&a);
        printf("root(%.2f) = %.4f\n", a, squareRoot(a, 0.00001));
        
        getchar();
        return 0;
}


float squareRoot(float num, float accuracy)
{	
	float guess = 1;
	float difference = num - guess * guess;
	float x;
	while(difference > accuracy)
	{
		x = num/guess;
		guess = (guess + x)/2;
		difference = num - guess * guess;	
	}
	return x;
}

I am currently trying to figure out what went wrong, my best guess is my while loop is wrong because it returns the answer x through only 1 iteration(1 loop) that is it goes through the while loop without even checking if difference>accuracy(0.0001) can anyone help out? thank you.

[stahta01]

Things like this use a absolute function on the difference look for abs or fabs in maybe math header/lib.

fabs - C++ Reference

Tim S.

[AFCKING]

Yes I have that #include "stdlib.h" I didn't copied it

[stahta01]

Yes I have that #include "stdlib.h" I didn't copied it

If this was supposed to make sense; it does NOT make any sense to me.

Do you realize that -2 is less than 1?
And, abs(-2) is NOT less than 1?

Tim S.

[AFCKING]

Right! since it returns a negative value for difference I need to use the absolute value. Thanks. Haha it took me long enough to understand.