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POSorting a 2 dimensional array of strings by a specific field
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copied!<p>Given a two dimensional array decalred below:</p> <pre><code>char * Arr[4] = { {"124 -346 DATA...."}, {"39479 -32 MOREDATA...."}, {"12 -1 DATA2...."}, {"100 -45 DATA4...."} }; </code></pre> <p>i'm trying to use <a href="http://www.cplusplus.com/reference/cstdlib/qsort/" rel="nofollow">qsort()</a> to sort this function according to the <strong>SECOND</strong> field, meaning the strings would be ordered according to the lowest second value(-1,-32,-45,-346). I know how to make this function if each value were only one digit, but the digits in the program could be arbitrarily long. here is what i have but the program crashes, if there is a more efficient way to sort this data i would love to here it(i know my method can't be very efficient).</p> <p>Sort function(which qsort() calls):</p> <pre><code>inline void GetStr(char *ix, char* Result) //call to get second number in function { char *spacing; //iterator to traverse spacing = ix; //iterator = pos of ix int LEN = 0; //length and offset int Offset = 0; while(*spacing != ' ') //while not at end of first num { Offset++; //offset is more spacing++; } spacing++; //go one ahead of the space Offset++; while(*spacing != ' ') //while not end of second number { spacing++; Offset++; LEN++; //length of number } strncpy(Result, ix + (Offset - LEN),LEN); } int sort(const void* a, const void* b) { char *ia = *(char**)a; char *ib = *(char**)b; char * Str; char * Str2; GetStr(ia, Str); //getting some strange errors....... program just crashes GetStr(ib, Str2); printf("Str: %s Str2: %s", Str, Str2); int n1 = atoi(Str); int n2 = atoi(Str2); return (n1 > n2); } </code></pre>

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