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19.2: Numeric to Character String Conversion

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    54385
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    An integer or real value can be converted into a character string using a write operation. The string is provided as the output variable instead of a file unit number. The numeric variable is provided as the input for the write operation.

    The following is a simple example that will convert an integer into a string and a real into a string. Some numeric operations are performed on the numeric values and then the resulting strings are concatenated with another string. Concatenation can only be performed on character data types.

    ! Example program to use an internal write for
    ! character / numeric conversion.
    
    program cvtExample2
    implicit none
    integer :: cvtErr
    character(50) :: str1, str2, msg1, msg2
    integer :: iNum=2468
    real :: pi = 3.14, tau
    
        write (*,'(a, /)') "Example Conversion Program."
    
    ! ----------
    !  Convert integer value to a string.
    
        iNum = iNum / 100
        write (str1, '(i3)', iostat=cvtErr) iNum
        
        if (cvtErr == 0 ) then
            msg1 = "My age is " // str1
            write (*,'(a, a)')                    &
                "Message 1 = ", msg1
        else
        
            write (*,'(a, /)') "Error, invalid conversion."      
        end if
    
    ! ----------
    !  Convert real value to a string.
    
        tau = pi * 2.0
        write (str2, '(f5.3)', iostat=cvtErr) tau
        
        if (cvtErr == 0 ) then
            msg2 = "The value of TAU is " // str2
            write (*,'(a, a, /)')                 &
                "Message 2 = ", msg2
        else
            write (*,'(a, /)') "Error, invalid conversion."
        end if
    
    end program cvtExample2
    

    An example of the output for this program is as follows:

    Example Conversion Program.
    
    Message 1 = My age is 124
    Message 2 = The value of TAU is 6.283
    

    Once the numeric values are converted into strings, the character functions and character operations can be used as needed.


    This page titled 19.2: Numeric to Character String Conversion is shared under a CC BY-NC-SA 3.0 license and was authored, remixed, and/or curated by Ed Jorgensen via source content that was edited to the style and standards of the LibreTexts platform.