while(_P){
        _P = false
        for (let _i = 1; _i<=_n-_k; _i += 1){
            if (_x[i] > _x[i+1]){
                if (x > 1){
                    switch(expression) {
                        case 3: {
                            break;
                        }
                        case 2: {
                            break;
                        }
                        default: {
                            break;
                        }
                    }
                }
                let _A = _x[i]
                _x[i] = _x[i+1]
                _x[i+1] = _A
                _P = true
            }
        }
        _k += 1
    }