向函数输入焓值和压强，通过函数查表得到温度，粘度等参数。函数
T_r431a[1]:=50.000;
T_r431a[2]:=51.000;
T_r431a[3]:=52.000;
T_r431a[4]:=53.000;
T_r431a[5]:=54.000;
T_r431a[6]:=55.000;
T_r431a[7]:=56.000;
rho_r431a[1]:=502.62;
rho_r431a[2]:=499.92;
rho_r431a[3]:=497.15;
rho_r431a[4]:=494.33;
rho_r431a[5]:=52.247;
rho_r431a[6]:=51.688;
rho_r431a[7]:=51.153;
H_r431a[1]:=1409.4;
H_r431a[2]:=1418.3;
H_r431a[3]:=1427.1;
H_r431a[4]:=1436.1;
H_r431a[5]:=2178.1;
H_r431a[6]:=2185.7;
H_r431a[7]:=2193.1;

判别公式为
for j in 1:24 loop
if H_r431a[j]<=Hr431a and Hr431a<=H_r431a[j+1]
then beita:=(T_r431a[j+1]-Tr431a)/(T_r431a[j+1]-T_r431a[j]);
rhor431a := rho_r431a[j+1]*(1-beita)+rho_r431a[j]beita;
cpr431a := cp_r431a[j+1](1-beita)+cp_r431a[j]beita;
yitar431a := yita_r431a[j+1](1-beita)+yita_r431a[j]beita;
lamdar431a := lamda_r431a[j+1](1-beita)+lamda_r431a[j]beita;
Tr431a := T_r431a[j+1](1-beita)+T_r431a[j]*beita;
为了辨别焓值处于哪一个位置
所以加入了判断
elseif Hr431a>H_r431a[25]
then rhor431a := 26;
cpr431a := 2200;
yitar431a := 0.000074293;
lamdar431a := 0.030881;
Tr431a :=360;
elseif Hr431a<H_r431a[1]
then rhor431a := 26;
cpr431a := 2200;
yitar431a := 0.000074293;
lamdar431a := 0.030881;
Tr431a :=330;
else
rhor431a := 26;
cpr431a := 2200;
yitar431a := 0.000074293;
lamdar431a := 0.030881;
Tr431a :=300;
然而，当输入焓值为1409.4时，判断给出的是else。即使是1410也是else语句；这是因为什么啊？明明焓值处于H_r431a[j]<=Hr431a and Hr431a<=H_r431a[j+1]中啊
附件中用到的文件是test和R431a