Qt 계산기좀 봐주세요

if(widget == Number0)
    {
        strBuf += QString("0");
    }
    else if(widget == Number1)
    {
        strBuf += QString("1");
    }
    else if(widget == Number2)
    {
        strBuf += QString("2");
    }
    else if(widget == Number3)
    {
        strBuf += QString("3");
    }
    else if(widget == Number4)
    {
        strBuf += QString("4");

    else if(widget == Plus)
    {
            strBuf += QString("+");
    }

else if(widget == Equal)
    {
        float value;
        value = strBuf();
        strBuf = QString("result:%f");
    }