problem of using const when passing a pointer-CodePudding

Visual studio shows a error saying "the object has type quantifiers that are not compatible with the member function 'somfunc' "

class T_ship {
    public:    
        ... 
        float ship_run(int ship_len);
        // function ship_run doesn't change any class member values
};

There is a function in main() with *T_ship pointer passed as input.

void draw_ship(const T_ship * a_shp){

    float dist = a_ship-> ship_run(100); 
    // there is a red wavy line under a_ship     
}

Many thanks if someone can help.

CodePudding user response：

If you want the actual pointer to be const and not the object pointed to, put the const in front of the type, so like this:

T_ship * const

However in your case if the function ship_run doesn't modify anything you should mark it as const at the end of the function as well so like this:

float ship_run(int v) const { /* your code here */ }