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< a href = "#func-members" > Functions< / a > < / div >
< div class = "headertitle" >
< div class = "title" > sol1.c File Reference< / div > < / div >
< / div > <!-- header -->
< div class = "contents" >
< p > < a href = "https://projecteuler.net/problem=8" > Problem 8< / a > solution
< a href = "#details" > More...< / a > < / p >
< div class = "textblock" > < code > #include < stdio.h> < / code > < br / >
< code > #include < stdlib.h> < / code > < br / >
< / div > < div class = "textblock" > < div class = "dynheader" >
Include dependency graph for sol1.c:< / div >
< div class = "dyncontent" >
< div class = "center" > < iframe scrolling = "no" frameborder = "0" src = "../../d8/d6a/problem__8_2sol1_8c__incl.svg" width = "160" height = "127" > < p > < b > This browser is not able to show SVG: try Firefox, Chrome, Safari, or Opera instead.< / b > < / p > < / iframe >
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< tr class = "heading" > < td colspan = "2" > < h2 class = "groupheader" > < a name = "func-members" > < / a >
Functions< / h2 > < / td > < / tr >
< tr class = "memitem:a9ffc8845f17b01a353767a40a3adf7bd" > < td class = "memItemLeft" align = "right" valign = "top" > long long int  < / td > < td class = "memItemRight" valign = "bottom" > < a class = "el" href = "../../dc/d63/problem__8_2sol1_8c.html#a9ffc8845f17b01a353767a40a3adf7bd" > get_product< / a > (FILE *fp, long start_pos, int num_digits)< / td > < / tr >
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< tr class = "memdesc:a9ffc8845f17b01a353767a40a3adf7bd" > < td class = "mdescLeft" >   < / td > < td class = "mdescRight" > Compute the product of two numbers in a file. < a href = "../../dc/d63/problem__8_2sol1_8c.html#a9ffc8845f17b01a353767a40a3adf7bd" > More...< / a > < br / > < / td > < / tr >
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int  < / td > < td class = "memItemRight" valign = "bottom" > < a class = "el" href = "../../dc/d63/problem__8_2sol1_8c.html#a0ddf1224851353fc92bfbff6f499fa97" > main< / a > (int argc, char *argv[])< / td > < / tr >
< tr class = "memdesc:a0ddf1224851353fc92bfbff6f499fa97" > < td class = "mdescLeft" >   < / td > < td class = "mdescRight" > Main function. < br / > < / td > < / tr >
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< tr class = "separator:a0ddf1224851353fc92bfbff6f499fa97" > < td class = "memSeparator" colspan = "2" >   < / td > < / tr >
< / table >
< a name = "details" id = "details" > < / a > < h2 class = "groupheader" > Detailed Description< / h2 >
< div class = "textblock" > < p > < a href = "https://projecteuler.net/problem=8" > Problem 8< / a > solution < / p >
< dl class = "section author" > < dt > Author< / dt > < dd > < a href = "https://github.com/kvedala" > Krishna Vedala< / a > < / dd > < / dl >
< / div > < h2 class = "groupheader" > Function Documentation< / h2 >
< a id = "a9ffc8845f17b01a353767a40a3adf7bd" > < / a >
< h2 class = "memtitle" > < span class = "permalink" > < a href = "#a9ffc8845f17b01a353767a40a3adf7bd" > ◆ < / a > < / span > get_product()< / h2 >
< div class = "memitem" >
< div class = "memproto" >
< table class = "memname" >
< tr >
< td class = "memname" > long long int get_product < / td >
< td > (< / td >
< td class = "paramtype" > FILE *  < / td >
< td class = "paramname" > < em > fp< / em > , < / td >
< / tr >
< tr >
< td class = "paramkey" > < / td >
< td > < / td >
< td class = "paramtype" > long  < / td >
< td class = "paramname" > < em > start_pos< / em > , < / td >
< / tr >
< tr >
< td class = "paramkey" > < / td >
< td > < / td >
< td class = "paramtype" > int  < / td >
< td class = "paramname" > < em > num_digits< / em >   < / td >
< / tr >
< tr >
< td > < / td >
< td > )< / td >
< td > < / td > < td > < / td >
< / tr >
< / table >
< / div > < div class = "memdoc" >
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< p > Compute the product of two numbers in a file. < / p >
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< dl class = "params" > < dt > Parameters< / dt > < dd >
< table class = "params" >
< tr > < td class = "paramdir" > [in]< / td > < td class = "paramname" > fp< / td > < td > pointer to file that is already open < / td > < / tr >
< tr > < td class = "paramdir" > [in]< / td > < td class = "paramname" > start_pos< / td > < td > line number of the first numer < / td > < / tr >
< tr > < td class = "paramdir" > [in]< / td > < td class = "paramname" > num_digits< / td > < td > number of digits on the line to multiply < / td > < / tr >
< / table >
< / dd >
< / dl >
< dl class = "section return" > < dt > Returns< / dt > < dd > expected product < / dd > < / dl >
< div class = "fragment" > < div class = "line" > < a name = "l00017" > < / a > < span class = "lineno" > 17< / span >   {< / div >
< div class = "line" > < a name = "l00018" > < / a > < span class = "lineno" > 18< / span >   < span class = "keywordtype" > char< / span > ch = < span class = "charliteral" > ' ' < / span > ; < span class = "comment" > /* temporary variable to store character read from file */< / span > < / div >
< div class = "line" > < a name = "l00019" > < / a > < span class = "lineno" > 19< / span >   < span class = "keywordtype" > unsigned< / span > < span class = "keywordtype" > char< / span > num = 0; < span class = "comment" > /* temporary variable to store digit read */< / span > < / div >
< div class = "line" > < a name = "l00020" > < / a > < span class = "lineno" > 20< / span >   < span class = "keywordtype" > long< / span > < span class = "keywordtype" > long< / span > < span class = "keywordtype" > int< / span > prod = 1; < span class = "comment" > /* product accumulator */< / span > < / div >
< div class = "line" > < a name = "l00021" > < / a > < span class = "lineno" > 21< / span >   < span class = "keywordtype" > int< / span > count =< / div >
< div class = "line" > < a name = "l00022" > < / a > < span class = "lineno" > 22< / span >   0; < span class = "comment" > /* we use this variable to count number of bytes of file read */< / span > < / div >
< div class = "line" > < a name = "l00023" > < / a > < span class = "lineno" > 23< / span >   < / div >
< div class = "line" > < a name = "l00024" > < / a > < span class = "lineno" > 24< / span >   < span class = "comment" > /* accumulate product for num_digits */< / span > < / div >
< div class = "line" > < a name = "l00025" > < / a > < span class = "lineno" > 25< / span >   < span class = "keywordflow" > for< / span > (< span class = "keywordtype" > int< / span > i = 0; i < num_digits; i++, count++)< / div >
< div class = "line" > < a name = "l00026" > < / a > < span class = "lineno" > 26< / span >   {< / div >
< div class = "line" > < a name = "l00027" > < / a > < span class = "lineno" > 27< / span >   < span class = "comment" > /* get character from file */< / span > < / div >
< div class = "line" > < a name = "l00028" > < / a > < span class = "lineno" > 28< / span >   ch = getc(fp);< / div >
< div class = "line" > < a name = "l00029" > < / a > < span class = "lineno" > 29< / span >   < / div >
< div class = "line" > < a name = "l00030" > < / a > < span class = "lineno" > 30< / span >   < span class = "comment" > /* the ASCII codes of digits is between 0x30 and 0x39.< / span > < / div >
< div class = "line" > < a name = "l00031" > < / a > < span class = "lineno" > 31< / span >   < span class = "comment" > * any character not in this range implies an invalid character< / span > < / div >
< div class = "line" > < a name = "l00032" > < / a > < span class = "lineno" > 32< / span >   < span class = "comment" > */< / span > < / div >
< div class = "line" > < a name = "l00033" > < / a > < span class = "lineno" > 33< / span >   < span class = "keywordflow" > if< / span > (ch < 0x30 || ch > 0x39)< / div >
< div class = "line" > < a name = "l00034" > < / a > < span class = "lineno" > 34< / span >   {< / div >
< div class = "line" > < a name = "l00035" > < / a > < span class = "lineno" > 35< / span >   < span class = "keywordflow" > if< / span > (ch == EOF)< / div >
< div class = "line" > < a name = "l00036" > < / a > < span class = "lineno" > 36< / span >   < span class = "keywordflow" > return< / span > 0;< / div >
< div class = "line" > < a name = "l00037" > < / a > < span class = "lineno" > 37< / span >   i--;< / div >
< div class = "line" > < a name = "l00038" > < / a > < span class = "lineno" > 38< / span >   < span class = "keywordflow" > continue< / span > ;< / div >
< div class = "line" > < a name = "l00039" > < / a > < span class = "lineno" > 39< / span >   }< / div >
< div class = "line" > < a name = "l00040" > < / a > < span class = "lineno" > 40< / span >   < / div >
< div class = "line" > < a name = "l00041" > < / a > < span class = "lineno" > 41< / span >   num = ch - 0x30; < span class = "comment" > /* convert character digit to number */< / span > < / div >
< div class = "line" > < a name = "l00042" > < / a > < span class = "lineno" > 42< / span >   < span class = "keywordflow" > if< / span > (num == 0)< / div >
< div class = "line" > < a name = "l00043" > < / a > < span class = "lineno" > 43< / span >   {< / div >
< div class = "line" > < a name = "l00044" > < / a > < span class = "lineno" > 44< / span >   < span class = "comment" > /* If number is zero, we can skip the next ' num_digits' < / span > < / div >
< div class = "line" > < a name = "l00045" > < / a > < span class = "lineno" > 45< / span >   < span class = "comment" > * because this ' 0' will repeat in the next ' num_digit' < / span > < / div >
< div class = "line" > < a name = "l00046" > < / a > < span class = "lineno" > 46< / span >   < span class = "comment" > * multiplications. Hence, we also do not update the file position< / span > < / div >
< div class = "line" > < a name = "l00047" > < / a > < span class = "lineno" > 47< / span >   < span class = "comment" > */< / span > < / div >
< div class = "line" > < a name = "l00048" > < / a > < span class = "lineno" > 48< / span >   < span class = "comment" > /* NOTE: this is not needed but helps get results faster :) */< / span > < / div >
< div class = "line" > < a name = "l00049" > < / a > < span class = "lineno" > 49< / span >   < span class = "keywordflow" > return< / span > 0;< / div >
< div class = "line" > < a name = "l00050" > < / a > < span class = "lineno" > 50< / span >   }< / div >
< div class = "line" > < a name = "l00051" > < / a > < span class = "lineno" > 51< / span >   < / div >
< div class = "line" > < a name = "l00052" > < / a > < span class = "lineno" > 52< / span >   prod *= num; < span class = "comment" > /* accumulate product */< / span > < / div >
< div class = "line" > < a name = "l00053" > < / a > < span class = "lineno" > 53< / span >   }< / div >
< div class = "line" > < a name = "l00054" > < / a > < span class = "lineno" > 54< / span >   < / div >
< div class = "line" > < a name = "l00055" > < / a > < span class = "lineno" > 55< / span >   < span class = "comment" > /* set file position to the next starting character + 1 */< / span > < / div >
< div class = "line" > < a name = "l00056" > < / a > < span class = "lineno" > 56< / span >   fseek(fp, -count + 1, SEEK_CUR);< / div >
< div class = "line" > < a name = "l00057" > < / a > < span class = "lineno" > 57< / span >   < / div >
< div class = "line" > < a name = "l00058" > < / a > < span class = "lineno" > 58< / span >   < span class = "keywordflow" > return< / span > prod;< / div >
< div class = "line" > < a name = "l00059" > < / a > < span class = "lineno" > 59< / span >   }< / div >
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< li class = "navelem" > < a class = "el" href = "../../dir_b3d331eabd4234f247030c297aaf021c.html" > project_euler< / a > < / li > < li class = "navelem" > < a class = "el" href = "../../dir_4a15c8553efb9e59e3f1091cc0d3a27d.html" > problem_8< / a > < / li > < li class = "navelem" > < a class = "el" href = "../../dc/d63/problem__8_2sol1_8c.html" > sol1.c< / a > < / li >
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