Porting a bit of Fortran 77 code. It appears that REAL variables are being assigned to INTEGER variables. I do not have a method to run this code and wonder what the behavior is in the following case:
REAL*4 A
A = 123.25
B = INT(A)
B = 123 or B = 124?
How about at the 0.5 mark?
REAL*4 C
C = 123.5
D = INT(C)
D = 123 or D = 123.5?
INT is always rounding down:
From the GCC documentation:
These functions return a INTEGER variable or array under the following rules:
(A) If A is of type INTEGER, INT(A) = A
(B) If A is of type REAL and |A| < 1, INT(A) equals 0. If |A| \geq 1, then INT(A) equals the largest integer that does not exceed the range of A and whose sign is the same as the sign of A.
(C) If A is of type COMPLEX, rule B is applied to the real part of A.
If you want to round to the nearest integer, use NINT.
So, in your case B and D are always 123 (if they are declared as integer).
Only as completion to the existing answers I want to add an example how the commercial rounds can be realized without using NINT by
L = INT(F + 0.5)
where L is INTEGER and F is a positive REAL number. I've found this in FORTRAN 77 code samples from the last century.
Extending this to negative REAL numbers by
L = SIGN(1.0,F)*INT(ABS(F) + 0.5)
and going back to the 80th of last century, the minimal code example looks like this
PROGRAM ROUNDTEST
DO 12345 I=0,30
F = -1.0 + I * 0.1
J = INT(F)
K = NINT(F)
L = SIGN(1.0,F)*INT(ABS(F) + 0.5)
PRINT *, I, F, J, K, L
12345 CONTINUE
END
which creates the output
$ ./ROUNDTEST
0 -1.00000000 -1 -1 -1
1 -0.899999976 0 -1 -1
2 -0.800000012 0 -1 -1
3 -0.699999988 0 -1 -1
4 -0.600000024 0 -1 -1
5 -0.500000000 0 -1 -1
6 -0.399999976 0 0 0
7 -0.300000012 0 0 0
8 -0.199999988 0 0 0
9 -9.99999642E-02 0 0 0
10 0.00000000 0 0 0
11 0.100000024 0 0 0
12 0.200000048 0 0 0
13 0.300000072 0 0 0
14 0.399999976 0 0 0
15 0.500000000 0 1 1
16 0.600000024 0 1 1
17 0.700000048 0 1 1
18 0.800000072 0 1 1
19 0.899999976 0 1 1
20 1.00000000 1 1 1
21 1.10000014 1 1 1
22 1.20000005 1 1 1
23 1.29999995 1 1 1
24 1.40000010 1 1 1
25 1.50000000 1 2 2
26 1.60000014 1 2 2
27 1.70000005 1 2 2
28 1.79999995 1 2 2
29 1.90000010 1 2 2
30 2.00000000 2 2 2
ROUNDTEST is compiled and linked by gfortran version 7.4.0 by
$ gfortran.exe ROUNDTEST.FOR -o ROUNDTEST
Hope this helps you if you have to deal with old FORTRAN code.