CODEWITHSUNDEEP
c++multidimensional-arraycompiler-errorsoperators
AGraham
AGraham

Reputation: 13

Multi-Dimensional Array class error

This code worked fine until I added the rot() function. Yes, it is declared properly in the header file. I replaced all the equation with simple 1.0f values but the same error occurred. That hints to me that it has something to do with declaring Matrix2f rot; ...Does anyone have any clue what the issue is here?

#include "Matrix2f.h"
#include <cmath>
#include <iostream>
#include "Vector2f.h"

Matrix2f::Matrix2f(){

    m[0][0]= 1.0f;    m[0][1]= 0.0f;
    m[1][0]= 0.0f;    m[1][1]= 1.0f;

}

Vector2f Matrix2f::rot(float theta, Vector2f vec){

     Matrix2f rot;

        rot[0][0]= cosf(theta);  rot[0][1]= -sinf(theta);
        rot[1][0]= sinf(theta);  rot[1][1]= cosf(theta);

        float tx = ((rot[0][0]*vec.getX())+(rot[0][1]*vec.getY()));
        float ty = ((rot[1][0]*vec.getX())+(rot[1][1]*vec.getY()));


    return Vector2f(tx, ty);

}

void Matrix2f::printMat(){

    std::cout << "| " << m[0][0] << "    " << m[0][1] << " |" << std::endl;
    std::cout << "| " << m[1][0] << "    " << m[1][1] << " |" << std::endl;
}

The error the compiler gives:

|17|error: no match for 'operator[]' in 'rot[0]'|

it gives the same code twice for each line from line 17 through line 21... Any help greatly appreciated :)

Upvotes: 1

Views: 52

Answers (2)

Icarus3
Icarus3

Reputation: 2350

First of all, you do not need "Matrix2f rot" object inside "rot" method.

You can change your method as:

Vector2f Matrix2f::rot(float theta, Vector2f vec){

    float tx = (( cosf(theta) * vec.getX())+( ( -sinf(theta) ) * vec.getY()));
    float ty = (( sinf(theta) * vec.getX())+( cosf(theta) * vec.getY()));

    return Vector2f(tx, ty);
}

Unless you want to reset the member variable "m" in "rot"( which I assume "float m[2][2]" ) then you can use:

Vector2f Matrix2f::rot(float theta, Vector2f vec){

    m[0][0]= cosf(theta);  m[0][1]= -sinf(theta);
    m[1][0]= sinf(theta);  m[1][1]= cosf(theta);

    float tx = (( m[0][0] * vec.getX())+( m[0][1] ) * vec.getY()));
    float ty = (( m[1][0] * vec.getX())+( m[1][1] * vec.getY()));

    return Vector2f(tx, ty);

}

You can not use rot[][] unless your class ( Matrix2f ) provides the implementation which overrides the operator []

Upvotes: 2

ruthless
ruthless

Reputation: 1140

You need to access the multidimensional array inside the object which is m. To do this, use rot.m as the multidimensional array.

Upvotes: 0

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