如何让单精和双精在混合运算时不会产生误差?

CString strOutput;
    float fA;    fA=(float)0.0123;
    strOutput.Format("%.3f",fA*10000);//改此句.3f即可
    pDC->TextOut(0,0,strOutput);float fSource;
    double dTmp1;
    
    fSource=0.0025;
    dTmp1=(double)fSource;
    
    dTmp1=dTmp1*1000000;
    CString strOutput;
    strOutput.Format("%.3f",dTmp1);//改此句即可.3f    pDC->TextOut(0,0,strOutput);