Question

Fortran想先读取事先建好的txt文件,再把读取的数据赋值入矩阵中怎么编程序

让下面的矩阵A（15,15）
第1行：0.75400.31800.21420.30240.18710.81460.06500.26240.37510.4784
0.07180.35510.98760.35420.7777
第2行：0.07660.56800.67530.26240.72230.73560.19390.09560.87600.8937
0.80270.45460.25480.03690.3925
第3行：0.45950.95550.26420.71420.81880.19300.93000.70770.14330.9851
0.01340.95390.64150.20190.5993
第4行：0.19520.53350.97920.15070.21950.94470.35940.25800.09670.8004
0.83920.91420.75390.55130.1892
第5行：0.51300.09280.26610.40790.88110.24260.90070.84440.43120.1299
0.54660.81510.18170.34330.1248
第6行：0.55090.30750.43730.08490.89120.17840.46380.55050.82170.0200
0.90960.85770.70660.23440.3007
第7行：0.19990.65410.42910.61810.20380.60430.11610.11520.86630.5654
0.06960.58670.90740.14920.0743
第8行：0.21050.39870.79810.49320.86670.27380.07930.95540.24390.1850
0.59780.64450.32730.75020.3131
第9行：0.82290.57530.51860.54360.04480.29480.30580.16790.20260.7747
0.66850.11360.67170.95140.0323
第10行：0.62730.27680.90610.26460.82420.00550.00480.48450.02200.7470
0.98400.67360.79410.57420.4022
行11：0.94610.93100.53540.69850.12290.66960.57750.04300.96020.9198
0.70060.16170.00010.75820.7533
第12行：0.26930.50400.35650.49500.85530.03180.01330.36720.04270.0045
0.35080.83210.47710.32660.7360
第13行：0.44370.62640.50970.72910.61050.13670.14120.46900.71150.4645
0.81840.75150.67420.03650.3628
第14行：0.63970.18780.21190.78830.05010.15410.49490.52440.76790.8171
0.99500.90850.55690.31970.5292
第15行：0.76470.93030.44070.65080.30740.45320.47110.03320.84160.0492
0.87070.05530.13960.74510.0954
构造矩阵B（9，9）包含了A矩阵里以下的行和列：
行2 4 5 6 10 11 13 14 15
列: 3 4 7 8 9 11 12 13 15
写出矩阵B的迹数（矩阵B的主对角线（从左上方至右下方的对角线）上各个元素的总和）保留4位小数点想把A矩阵里的数据读入TXT文件，然后在TXT文件里读取B矩阵的行列，请问该怎么用FORTRAN实现。

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Answer 1

open(10,file='filename',action='read')
do i=1,15
do j=1,15
read(10,*)var(i,j)
end do
end do

追问

你好，我补充了一下问题，能再帮忙解决一下，可以吗？

追答

直接打开一个文件读入
open(20,file='filename.txt',action='write')
do i=1,15
do j=1,15
write(20,"(15f)") (var(i,j),j=1,15)
end do
end do
close(20)