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copied!<p>Jester and plinth's answers are broadly correct, but flawed. There is indeed no way to make the stock number-parsing routines (<code>*scanf</code>, <code>atof</code>, <code>strtod</code>) process a number in the format you have. However, the suggested workarounds are bad. First off, it is my personal opinion that <code>*scanf</code> and <code>ato*</code> should never be used, due to their horrifically bad handling of malformed input. More seriously, decimal-to-float conversion requires extended-precision arithmetic to avoid loss of accuracy. <code>strtod</code> (which is the routine that <em>should</em> be used for this problem) can be relied on to do this correctly, but processing the mantissa and exponent separately and then combining them in the obvious fashion does <em>not</em>. You need an intermediate type bigger than <code>double</code> and you need powers of 10 that are accurately computed all the way to the last bit, which <code>pow</code> doesn't reliably give you.</p> <p>So my recommendation is to rewrite each line on the fly to make it acceptable to <code>strtod</code>.</p> <ol> <li>Read each line into a pair of string buffers, splitting at <code>\t</code>. I would do this by hand, but you can <em>probably</em> get away with using <code>fscanf</code> as long as you only use <code>%s</code> formats. Make sure that each buffer has at least two extra bytes of space available.</li> <li>Scan each buffer for the <code>+</code> or <code>-</code>. Use <code>memmove</code> to shift that and all subsequent bytes of the string down one. Poke an <code>e</code> into the buffer at the original position of the sign. (If you do step 1 by hand you can combine this step with the loop for that step.)</li> <li>You now have the number in a format that <code>strtod</code> can process.</li> </ol>

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