comparison between pointer and integer [enabled by default]

Question

I want to check result with geo_analyzer function using by check_line and check_triangle. Thank you for appreciated answers. I don't know why I get the error. Besides I compile on ubuntu I get error here

if(check_line==1)    
return 1; // line

if(check_triangle==1)

return 2; //triangle

code of the function in function

double calculateSlop(double a,double b,double c,double d){

    return (d-c)/(b-a); // like (y2-y1)/(x2-x1)
}

int geo_analyzer( double p1_x, double p1_y, double p2_x, double
    p2_y, double p3_x, double p3_y, double p4_x, double p4_y){

        double m1,m2,m3;

        m1=calculateSlop(p1_x,p2_x,p1_y,p2_y);
        m2=calculateSlop(p2_x,p3_x,p2_y,p3_y);
        m3=calculateSlop(p3_x,p4_x,p3_y,p4_y);

        if(check_line==1){
        return 1; // line
        }
        if(check_triangle==1){
        return 2; //triangle
    }
}

Answer 1

You are comparing a function pointer with an integer. If you need the output of the function, call it by check_line(arg1, arg2, arg3, ...) .

Answer 2

Are check_line and check_triangle functions or variables?
When you write if(check_line==1) and if(check_triangle==1) you are actually saying that there are variables called "check_line" and "check_triangle" and you want to know if they are equal to the integer 1.
If you want to check if the OUTPUT of the functions "check_line" and "check_triangle" are equal to integer 1, then what you want do is verify what arguments you want to pass to these functions and write if ( check_line(argument1, argument2, ...)==1 ) and so on.