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< div class = "headertitle" > < div class = "title" > sol1.c File Reference< / div > < / div >
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< p > < a href = "https://projecteuler.net/problem=21" target = "_blank" > Problem 21< / a > solution
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< a href = "#details" > More...< / a > < / p >
< div class = "textblock" > < code > #include < stdio.h> < / code > < br / >
< code > #include < stdlib.h> < / code > < br / >
< code > #include < time.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 = "../../d3/d01/problem__21_2sol1_8c__incl.svg" width = "243" 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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< / div > < table class = "memberdecls" >
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< tr class = "heading" > < td colspan = "2" > < h2 class = "groupheader" > < a id = "func-members" name = "func-members" > < / a >
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Functions< / h2 > < / td > < / tr >
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< tr class = "memitem:aacf4b7e708651d2164e86958f2c29c93" > < td class = "memItemLeft" align = "right" valign = "top" > unsigned long  < / td > < td class = "memItemRight" valign = "bottom" > < a class = "el" href = "../../df/d1a/problem__21_2sol1_8c.html#aacf4b7e708651d2164e86958f2c29c93" > sum_of_divisors< / a > (unsigned int N)< / td > < / tr >
< tr class = "memdesc:aacf4b7e708651d2164e86958f2c29c93" > < td class = "mdescLeft" >   < / td > < td class = "mdescRight" > function to return the sum of proper divisors of N < a href = "../../df/d1a/problem__21_2sol1_8c.html#aacf4b7e708651d2164e86958f2c29c93" > More...< / a > < br / > < / td > < / tr >
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< tr class = "separator:aacf4b7e708651d2164e86958f2c29c93" > < td class = "memSeparator" colspan = "2" >   < / td > < / tr >
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< tr class = "memitem:a3c04138a5bfe5d72780bb7e82a18e627" > < td class = "memItemLeft" align = "right" valign = "top" > int  < / td > < td class = "memItemRight" valign = "bottom" > < a class = "el" href = "../../df/d1a/problem__21_2sol1_8c.html#a3c04138a5bfe5d72780bb7e82a18e627" > main< / a > (int argc, char **argv)< / td > < / tr >
< tr class = "memdesc:a3c04138a5bfe5d72780bb7e82a18e627" > < td class = "mdescLeft" >   < / td > < td class = "mdescRight" > Main function. < a href = "../../df/d1a/problem__21_2sol1_8c.html#a3c04138a5bfe5d72780bb7e82a18e627" > More...< / a > < br / > < / td > < / tr >
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< / table >
< a name = "details" id = "details" > < / a > < h2 class = "groupheader" > Detailed Description< / h2 >
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< div class = "textblock" > < p > < a href = "https://projecteuler.net/problem=21" target = "_blank" > Problem 21< / a > solution < / p >
< dl class = "section author" > < dt > Author< / dt > < dd > < a href = "https://github.com/kvedala" target = "_blank" > Krishna Vedala< / a > < / dd > < / dl >
< / div > < h2 class = "groupheader" > Function Documentation< / h2 >
< a id = "a3c04138a5bfe5d72780bb7e82a18e627" name = "a3c04138a5bfe5d72780bb7e82a18e627" > < / a >
< h2 class = "memtitle" > < span class = "permalink" > < a href = "#a3c04138a5bfe5d72780bb7e82a18e627" > ◆ < / a > < / span > main()< / h2 >
< div class = "memitem" >
< div class = "memproto" >
< table class = "memname" >
< tr >
< td class = "memname" > int main < / td >
< td > (< / td >
< td class = "paramtype" > int  < / td >
< td class = "paramname" > < em > argc< / em > , < / td >
< / tr >
< tr >
< td class = "paramkey" > < / td >
< td > < / td >
< td class = "paramtype" > char **  < / td >
< td class = "paramname" > < em > argv< / em >   < / td >
< / tr >
< tr >
< td > < / td >
< td > )< / td >
< td > < / td > < td > < / td >
< / tr >
< / table >
< / div > < div class = "memdoc" >
< p > Main function. < / p >
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< div class = "fragment" > < div class = "line" > < span class = "lineno" > 37< / span > {< / div >
< div class = "line" > < span class = "lineno" > 38< / span > < span class = "keywordtype" > unsigned< / span > < span class = "keywordtype" > long< / span > sum = 0;< / div >
< div class = "line" > < span class = "lineno" > 39< / span > < span class = "keywordtype" > unsigned< / span > < span class = "keywordtype" > int< / span > MAX_N = 500;< / div >
< div class = "line" > < span class = "lineno" > 40< / span > < span class = "keywordflow" > if< / span > (argc == 2)< / div >
< div class = "line" > < span class = "lineno" > 41< / span > MAX_N = atoi(argv[1]);< / div >
< div class = "line" > < span class = "lineno" > 42< / span > < / div >
< div class = "line" > < span class = "lineno" > 43< / span > < span class = "comment" > /*< / span > < / div >
< div class = "line" > < span class = "lineno" > 44< / span > < span class = "comment" > * We use an array of flags to check if a number at the index was:< / span > < / div >
< div class = "line" > < span class = "lineno" > 45< / span > < span class = "comment" > * not-processed = 0< / span > < / div >
< div class = "line" > < span class = "lineno" > 46< / span > < span class = "comment" > * is amicable = 1< / span > < / div >
< div class = "line" > < span class = "lineno" > 47< / span > < span class = "comment" > * not amicable = -1< / span > < / div >
< div class = "line" > < span class = "lineno" > 48< / span > < span class = "comment" > */< / span > < / div >
< div class = "line" > < span class = "lineno" > 49< / span > < span class = "keywordtype" > char< / span > *flags = (< span class = "keywordtype" > char< / span > *)< a class = "code hl_define" href = "../../d2/ddd/malloc__dbg_8h.html#afdddaa949a93c1ef559a638e98f9c21b" > calloc< / a > (MAX_N, < span class = "keyword" > sizeof< / span > (< span class = "keywordtype" > char< / span > ));< / div >
< div class = "line" > < span class = "lineno" > 50< / span > < / div >
< div class = "line" > < span class = "lineno" > 51< / span > clock_t start_time = clock();< / div >
< div class = "line" > < span class = "lineno" > 52< / span > < span class = "keywordtype" > int< / span > i;< / div >
< div class = "line" > < span class = "lineno" > 53< / span > < span class = "comment" > /* there are no such numbers till 10. Lets search from there on */< / span > < / div >
< div class = "line" > < span class = "lineno" > 54< / span > < span class = "keywordflow" > for< / span > (i = 10; i < MAX_N; i++)< / div >
< div class = "line" > < span class = "lineno" > 55< / span > {< / div >
< div class = "line" > < span class = "lineno" > 56< / span > < span class = "keywordflow" > if< / span > (flags[i] != 0)< / div >
< div class = "line" > < span class = "lineno" > 57< / span > < span class = "comment" > /* already processed, skip */< / span > < / div >
< div class = "line" > < span class = "lineno" > 58< / span > < span class = "keywordflow" > continue< / span > ;< / div >
< div class = "line" > < span class = "lineno" > 59< / span > < / div >
< div class = "line" > < span class = "lineno" > 60< / span > < span class = "keywordtype" > unsigned< / span > < span class = "keywordtype" > int< / span > b = < a class = "code hl_function" href = "../../df/d1a/problem__21_2sol1_8c.html#aacf4b7e708651d2164e86958f2c29c93" > sum_of_divisors< / a > (i);< / div >
< div class = "line" > < span class = "lineno" > 61< / span > < span class = "keywordflow" > if< / span > (b > = MAX_N)< / div >
< div class = "line" > < span class = "lineno" > 62< / span > flags[i] = -1;< / div >
< div class = "line" > < span class = "lineno" > 63< / span > < span class = "keywordflow" > else< / span > < span class = "keywordflow" > if< / span > (flags[b] == -1)< / div >
< div class = "line" > < span class = "lineno" > 64< / span > < span class = "keywordflow" > continue< / span > ;< / div >
< div class = "line" > < span class = "lineno" > 65< / span > < / div >
< div class = "line" > < span class = "lineno" > 66< / span > < span class = "keywordtype" > unsigned< / span > < span class = "keywordtype" > int< / span > c = < a class = "code hl_function" href = "../../df/d1a/problem__21_2sol1_8c.html#aacf4b7e708651d2164e86958f2c29c93" > sum_of_divisors< / a > (b);< / div >
< div class = "line" > < span class = "lineno" > 67< / span > < span class = "keywordflow" > if< / span > (c == i & & b != i)< / div >
< div class = "line" > < span class = "lineno" > 68< / span > {< / div >
< div class = "line" > < span class = "lineno" > 69< / span > < span class = "comment" > /* found amicable */< / span > < / div >
< div class = "line" > < span class = "lineno" > 70< / span > flags[b] = 1;< / div >
< div class = "line" > < span class = "lineno" > 71< / span > flags[i] = 1;< / div >
< div class = "line" > < span class = "lineno" > 72< / span > sum += b + i;< / div >
< div class = "line" > < span class = "lineno" > 73< / span > < span class = "preprocessor" > #ifdef DEBUG< / span > < / div >
< div class = "line" > < span class = "lineno" > 74< / span > printf(< span class = "stringliteral" > " Amicable: %4d : %4d\n" < / span > , i, b);< / div >
< div class = "line" > < span class = "lineno" > 75< / span > < span class = "preprocessor" > #endif< / span > < / div >
< div class = "line" > < span class = "lineno" > 76< / span > }< / div >
< div class = "line" > < span class = "lineno" > 77< / span > < span class = "keywordflow" > else< / span > < / div >
< div class = "line" > < span class = "lineno" > 78< / span > {< / div >
< div class = "line" > < span class = "lineno" > 79< / span > flags[i] = -1;< / div >
< div class = "line" > < span class = "lineno" > 80< / span > < span class = "keywordflow" > if< / span > (b < MAX_N)< / div >
< div class = "line" > < span class = "lineno" > 81< / span > flags[b] = -1;< / div >
< div class = "line" > < span class = "lineno" > 82< / span > }< / div >
< div class = "line" > < span class = "lineno" > 83< / span > }< / div >
< div class = "line" > < span class = "lineno" > 84< / span > < / div >
< div class = "line" > < span class = "lineno" > 85< / span > clock_t end_time = clock();< / div >
< div class = "line" > < span class = "lineno" > 86< / span > < / div >
< div class = "line" > < span class = "lineno" > 87< / span > printf(< span class = "stringliteral" > " \nTime taken: %.4g millisecond\n" < / span > ,< / div >
< div class = "line" > < span class = "lineno" > 88< / span > 1e3 * (end_time - start_time) / CLOCKS_PER_SEC);< / div >
< div class = "line" > < span class = "lineno" > 89< / span > printf(< span class = "stringliteral" > " Sum of all numbers = %lu\n" < / span > , sum);< / div >
< div class = "line" > < span class = "lineno" > 90< / span > < / div >
< div class = "line" > < span class = "lineno" > 91< / span > < a class = "code hl_define" href = "../../d2/ddd/malloc__dbg_8h.html#a9cc854374299a1dd933bf62029761768" > free< / a > (flags);< / div >
< div class = "line" > < span class = "lineno" > 92< / span > < span class = "keywordflow" > return< / span > 0;< / div >
< div class = "line" > < span class = "lineno" > 93< / span > }< / div >
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< div class = "ttc" id = "amalloc__dbg_8h_html_a9cc854374299a1dd933bf62029761768" > < div class = "ttname" > < a href = "../../d2/ddd/malloc__dbg_8h.html#a9cc854374299a1dd933bf62029761768" > free< / a > < / div > < div class = "ttdeci" > #define free(ptr)< / div > < div class = "ttdoc" > This macro replace the standard free function with free_dbg.< / div > < div class = "ttdef" > < b > Definition:< / b > malloc_dbg.h:26< / div > < / div >
< div class = "ttc" id = "amalloc__dbg_8h_html_afdddaa949a93c1ef559a638e98f9c21b" > < div class = "ttname" > < a href = "../../d2/ddd/malloc__dbg_8h.html#afdddaa949a93c1ef559a638e98f9c21b" > calloc< / a > < / div > < div class = "ttdeci" > #define calloc(elemCount, elemSize)< / div > < div class = "ttdoc" > This macro replace the standard calloc function with calloc_dbg.< / div > < div class = "ttdef" > < b > Definition:< / b > malloc_dbg.h:22< / div > < / div >
< div class = "ttc" id = "aproblem__21_2sol1_8c_html_aacf4b7e708651d2164e86958f2c29c93" > < div class = "ttname" > < a href = "../../df/d1a/problem__21_2sol1_8c.html#aacf4b7e708651d2164e86958f2c29c93" > sum_of_divisors< / a > < / div > < div class = "ttdeci" > unsigned long sum_of_divisors(unsigned int N)< / div > < div class = "ttdoc" > function to return the sum of proper divisors of N< / div > < div class = "ttdef" > < b > Definition:< / b > sol1.c:13< / div > < / div >
< / div > <!-- fragment --> < div class = "dynheader" >
Here is the call graph for this function:< / div >
< div class = "dyncontent" >
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< div class = "center" > < iframe scrolling = "no" frameborder = "0" src = "../../df/d1a/problem__21_2sol1_8c_a3c04138a5bfe5d72780bb7e82a18e627_cgraph.svg" width = "227" height = "38" > < p > < b > This browser is not able to show SVG: try Firefox, Chrome, Safari, or Opera instead.< / b > < / p > < / iframe >
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< / div >
< / div >
< / div >
< / div >
< a id = "aacf4b7e708651d2164e86958f2c29c93" name = "aacf4b7e708651d2164e86958f2c29c93" > < / a >
< h2 class = "memtitle" > < span class = "permalink" > < a href = "#aacf4b7e708651d2164e86958f2c29c93" > ◆ < / a > < / span > sum_of_divisors()< / h2 >
< div class = "memitem" >
< div class = "memproto" >
< table class = "memname" >
< tr >
< td class = "memname" > unsigned long sum_of_divisors < / td >
< td > (< / td >
< td class = "paramtype" > unsigned int  < / td >
< td class = "paramname" > < em > N< / em > < / td > < td > )< / td >
< td > < / td >
< / tr >
< / table >
< / div > < div class = "memdoc" >
< p > function to return the sum of proper divisors of N < / p >
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< div class = "fragment" > < div class = "line" > < span class = "lineno" > 14< / span > {< / div >
< div class = "line" > < span class = "lineno" > 15< / span > < span class = "keywordtype" > unsigned< / span > < span class = "keywordtype" > long< / span > sum = 1 + N; < span class = "comment" > /* 1 and itself are always a divisor */< / span > < / div >
< div class = "line" > < span class = "lineno" > 16< / span > < span class = "comment" > /* divisors are symmertically distributed about the square-root */< / span > < / div >
< div class = "line" > < span class = "lineno" > 17< / span > < span class = "keywordflow" > for< / span > (< span class = "keywordtype" > unsigned< / span > < span class = "keywordtype" > int< / span > i = 2; i * i < N; i++)< / div >
< div class = "line" > < span class = "lineno" > 18< / span > {< / div >
< div class = "line" > < span class = "lineno" > 19< / span > < span class = "keywordflow" > if< / span > ((N % i) != 0)< / div >
< div class = "line" > < span class = "lineno" > 20< / span > < span class = "comment" > /* i is not a divisor of N */< / span > < / div >
< div class = "line" > < span class = "lineno" > 21< / span > < span class = "keywordflow" > continue< / span > ;< / div >
< div class = "line" > < span class = "lineno" > 22< / span > < / div >
< div class = "line" > < span class = "lineno" > 23< / span > < span class = "comment" > // #ifdef DEBUG< / span > < / div >
< div class = "line" > < span class = "lineno" > 24< / span > < span class = "comment" > // printf(" %4d, %4d," , i, N / i);< / span > < / div >
< div class = "line" > < span class = "lineno" > 25< / span > < span class = "comment" > // #endif< / span > < / div >
< div class = "line" > < span class = "lineno" > 26< / span > < / div >
< div class = "line" > < span class = "lineno" > 27< / span > sum += i + (N / i);< / div >
< div class = "line" > < span class = "lineno" > 28< / span > }< / div >
< div class = "line" > < span class = "lineno" > 29< / span > < span class = "comment" > // #ifdef DEBUG< / span > < / div >
< div class = "line" > < span class = "lineno" > 30< / span > < span class = "comment" > // printf(" \nSum of divisors of %4d: %4d\n" , N, sum);< / span > < / div >
< div class = "line" > < span class = "lineno" > 31< / span > < span class = "comment" > // #endif< / span > < / div >
< div class = "line" > < span class = "lineno" > 32< / span > < span class = "keywordflow" > return< / span > sum;< / div >
< div class = "line" > < span class = "lineno" > 33< / span > }< / div >
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< / div > <!-- fragment -->
< / div >
< / div >
< / div > <!-- contents -->
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< / div > <!-- doc - content -->
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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_d9e100c82ada2163abea49688a71e81c.html" > problem_21< / a > < / li > < li class = "navelem" > < a class = "el" href = "../../df/d1a/problem__21_2sol1_8c.html" > sol1.c< / a > < / li >
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< li class = "footer" > Generated by < a href = "https://www.doxygen.org/index.html" > < img class = "footer" src = "../../doxygen.svg" width = "104" height = "31" alt = "doxygen" / > < / a > 1.9.3 < / li >
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