Simply fortran write to console10/31/2022 For historical reasons, if a format is specified to be real (floating point) but no decimal point is included in the data, the compiler inserts it based on the format. In Fortran it is best to avoid formatted input as much as possible, as it can lead to errors. Traditionally the format is placed immediately below the line which refers to it, or else all format statements are grouped together just before the end statement of their program unit. The second parameter to the write is then an integer statement label. It can still be useful for a particularly complex format (to keep the write statement short and readable) or for formats that are repeated in many write statements. It is the only non-executable statement that can do so. Write(*,'(a,f8.2,/,a,i6)') mess1,x,mess2,iĪ format string may be a variable character(len=32) :: formatstrįormat statements are abundant in older code, before the strings could be inserted into writes.įORMAT is non-executable but can appear anywhere in the source. It is useful for particularly long strings, however. The format statement is older and will be in old code, but it is usually harder to see what is happening. In the write it is enclosed in parentheses and quotes.įor most purposes it is best to put the format string into the write statement. The format string can be placed directly into the write statement or it can be in a separate format statement. Unlike some other languages, literal strings are never included, but must have their own edit descriptors. #Simply fortran write to console how to#The format string is constructed as a list of how to output the variables. The p descriptor applies till the next scale factor is encountered. Some modifiers can change the appearance of the output. ES causes it to write with the leading digit between 1 and 9, which is what most humans can read most easily. The default exponential format writes in machine normalization, with the leading digit between 0 and 1. G allows the compiler to choose whether to use decimal or exponential format. The real descriptors F, E, G, and D all work for both single and double precision. !write an EOL and go to the next line (record) within the format I !integerĭ !double precision (prints D rather than E for exponent)Ī !character (does not require a field width in most cases) Common Edit DescriptorsĪs usual, they are not case sensitive. If the field width is specified and the requested literal does not fit, the compiler will output a string of asterisks, e.g. When written as iF.m they will be printed with at least m digits and the rest of the field zero-filled on the left if all of F is not needed. Integers can be written as iF and any of the F spaces not needed will be blank filled, with the digits right justified. Strings take only RaF and do not usually require the F since the length will be known to the compiler. For floating-point numbers, Ra.0 will print the integer part. If you are willing to let the compiler calculate the number of characters to use, then Ra0.w alone works. Where R is a repeat count, a is the descriptor, F is the total field width including space for +-, and if requested +-e and exponent, and w is the number of digits to the right of the decimal point. The edit descriptor modifies how to output the variables. Formatted output is frequently required for legibility.įormatted output in Fortran is similar to other languages (the general layout descends from Fortran, the oldest higher-level programming language). But that frequently results in sprawling output that is difficult to read.
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