C语言代码转换为Fortran语言示例

以下展示了如何将一段简单的C语言代码转换为等效的Fortran代码：

 if(temp>=446.0 && temp<456.0)
  {
  HMXr11=((HMXk*temp)/HMXh)*exp((temp*HMXSf1-HMXEf1)/(R*temp));
  HMXr12=((HMXk*temp)/HMXh)*exp((temp*HMXSr1-HMXEr1)/(R*temp));
  HMXr21=((HMXk*temp)/HMXh)*exp((temp*HMXSf2-HMXEf2)/(R*temp));
  HMXr22=((HMXk*temp)/HMXh)*exp((temp*HMXSr2-HMXEr2)/(R*temp));
  HMXr3=HMXZ3*exp(-HMXEf3/(R*temp));
  HMXr4=HMXZ4*exp(-HMXEf4/(R*temp));
  if(C_UDMI(cell,thread,0)>=C_UDMI(cell,thread,1))
  {
  HMXd0=-(C_UDMI(cell,thread,0)*HMXr11-C_UDMI(cell,thread,1)*HMXr12)-(C_UDMI(cell,thread,0)*C_UDMI(cell,thread,1)*(HMXr21-HMXr22));
  HMXd1=(C_UDMI(cell,thread,0)*HMXr11-C_UDMI(cell,thread,1)*HMXr12)+(C_UDMI(cell,thread,0)*C_UDMI(cell,thread,1)*(HMXr21-HMXr22))-(C_UDMI(cell,thread,1)*HMXr3)-(C_UDMI(cell,thread,1)*C_UDMI(cell,thread,2)*HMXr4);
  HMXd2=(C_UDMI(cell,thread,1)*HMXr3)+(C_UDMI(cell,thread,1)*C_UDMI(cell,thread,2)*HMXr4);
  }
  if(C_UDMI(cell,thread,0)<C_UDMI(cell,thread,1))
  {
  HMXd0=-C_UDMI(cell,thread,0)*HMXr11-C_UDMI(cell,thread,0)*C_UDMI(cell,thread,1)*HMXr21;
  HMXd1=C_UDMI(cell,thread,0)*HMXr11+(C_UDMI(cell,thread,0)*C_UDMI(cell,thread,1)*HMXr21)-(C_UDMI(cell,thread,1)*HMXr3)-(C_UDMI(cell,thread,1)*C_UDMI(cell,thread,2)*HMXr4);
  HMXd2=(C_UDMI(cell,thread,1)*HMXr3)+(C_UDMI(cell,thread,1)*C_UDMI(cell,thread,2)*HMXr4);
  }
  C_UDMI(cell,thread,0)=C_UDMI(cell,thread,0)+HMXd0*ts;
  C_UDMI(cell,thread,1)=C_UDMI(cell,thread,1)+HMXd1*ts;
  C_UDMI(cell,thread,2)=C_UDMI(cell,thread,2)+HMXd2*ts;
  HMXsource1=HMXp*HMXQ1*(C_UDMI(cell,thread,0)*HMXr11-C_UDMI(cell,thread,1)*HMXr12);
  HMXsource2=HMXp*HMXQ2*(C_UDMI(cell,thread,0)*C_UDMI(cell,thread,1)*(HMXr21-HMXr22));
  HMXsource3=HMXp*HMXQ3*(C_UDMI(cell,thread,1)*HMXr3);
  HMXsource4=HMXp*HMXQ4*(C_UDMI(cell,thread,1)*C_UDMI(cell,thread,2)*HMXr4);	
  }

IF (temp>=446.0 .AND. temp<456.0) THEN
  HMXr11=((HMXk*temp)/HMXh)*EXP((temp*HMXSf1-HMXEf1)/(R*temp))
  HMXr12=((HMXk*temp)/HMXh)*EXP((temp*HMXSr1-HMXEr1)/(R*temp))
  HMXr21=((HMXk*temp)/HMXh)*EXP((temp*HMXSf2-HMXEf2)/(R*temp))
  HMXr22=((HMXk*temp)/HMXh)*EXP((temp*HMXSr2-HMXEr2)/(R*temp))
  HMXr3=HMXZ3*EXP(-HMXEf3/(R*temp))
  HMXr4=HMXZ4*EXP(-HMXEf4/(R*temp))
  IF (C_UDMI(cell,thread,0)>=C_UDMI(cell,thread,1)) THEN
    HMXd0=-(C_UDMI(cell,thread,0)*HMXr11-C_UDMI(cell,thread,1)*HMXr12)-(C_UDMI(cell,thread,0)*C_UDMI(cell,thread,1)*(HMXr21-HMXr22))
    HMXd1=(C_UDMI(cell,thread,0)*HMXr11-C_UDMI(cell,thread,1)*HMXr12)+(C_UDMI(cell,thread,0)*C_UDMI(cell,thread,1)*(HMXr21-HMXr22))-(C_UDMI(cell,thread,1)*HMXr3)-(C_UDMI(cell,thread,1)*C_UDMI(cell,thread,2)*HMXr4)
    HMXd2=(C_UDMI(cell,thread,1)*HMXr3)+(C_UDMI(cell,thread,1)*C_UDMI(cell,thread,2)*HMXr4)
  END IF
  IF (C_UDMI(cell,thread,0)<C_UDMI(cell,thread,1)) THEN
    HMXd0=-C_UDMI(cell,thread,0)*HMXr11-C_UDMI(cell,thread,0)*C_UDMI(cell,thread,1)*HMXr21
    HMXd1=C_UDMI(cell,thread,0)*HMXr11+(C_UDMI(cell,thread,0)*C_UDMI(cell,thread,1)*HMXr21)-(C_UDMI(cell,thread,1)*HMXr3)-(C_UDMI(cell,thread,1)*C_UDMI(cell,thread,2)*HMXr4)
    HMXd2=(C_UDMI(cell,thread,1)*HMXr3)+(C_UDMI(cell,thread,1)*C_UDMI(cell,thread,2)*HMXr4)
  END IF
  C_UDMI(cell,thread,0)=C_UDMI(cell,thread,0)+HMXd0*ts
  C_UDMI(cell,thread,1)=C_UDMI(cell,thread,1)+HMXd1*ts
  C_UDMI(cell,thread,2)=C_UDMI(cell,thread,2)+HMXd2*ts
  HMXsource1=HMXp*HMXQ1*(C_UDMI(cell,thread,0)*HMXr11-C_UDMI(cell,thread,1)*HMXr12)
  HMXsource2=HMXp*HMXQ2*(C_UDMI(cell,thread,0)*C_UDMI(cell,thread,1)*(HMXr21-HMXr22))
  HMXsource3=HMXp*HMXQ3*(C_UDMI(cell,thread,1)*HMXr3)
  HMXsource4=HMXp*HMXQ4*(C_UDMI(cell,thread,1)*C_UDMI(cell,thread,2)*HMXr4)
END IF

在这个示例中，我们将C语言中的 if 语句转换为 Fortran 中的 IF...THEN...END IF 结构，并将 && 运算符替换为 .AND.。此外，C语言中的 exp() 函数对应于 Fortran 中的 EXP() 函数。

需要注意的是，C语言中的 = 是赋值运算符，而在 Fortran 中，= 用于比较运算符，赋值运算符使用 = 符号。

通过这些简单的转换步骤，您可以将大多数C语言代码转换为等效的Fortran代码。