C qsort not working correctly

Question

I don\'t know what I\'m doing wrong but the following code does not sort the array properly.

#include 
#include 

int compare(         


        

Answer 1

I'm giving a code example using the information above. In my compiler and system, I get the same results as Ram who asked the question. This indicates that my integers are something like Ram's integers. I modified my code along the lines suggested by Mehrdad to use comparison operators instead of a subtraction. Then I got the numbers sorted properly.

Here is the code:

    #include 
    #include 

    int compare(const void* a, const void* b)
    {
        int
            n1 = * (int *) a,
            n2 = * (int *) b;

        /*
        Usine the ternary to express along the lines of
            if
            elseif
            elseif
            .
            .
            .
            else
        */

        return 
            n1 > n2             // if
            ? 1                 // then
            : n1 == n2          // else if
            ? 0                 // then
            : -1                // else
            ;                   // end if
    }

    int main(int argc, char * argv[])
    {
        int x[] = 
        { 
            -919238029, -889150029, -826670576, -579609061, -569653113, -305140505, -216823425, -193439331,
            -167683147, -49487019,  -45223520,  271789961,  275570429,  444855014,  559132135,  612312607,
            664554739,  677860351,  1005278191, 1031629361, 1089012280, 1115952521, 1521112993, 1530518916,
            1907515865, 1931470931, -1631034645,-1593702794,-1465300620,-1263094822
        };

        int 
            i = 0,                          // index
            imax = sizeof(x)/sizeof(int);   // max value for index

        FILE * outf = 0;

        if ( !(outf = fopen("output.txt", "wt")) )
        {
            puts("outf == 0 which is an error trying to open \"output.txt\" for writing.\n");
            getch();
            return;
        }

        qsort(x, imax, sizeof(int), compare);


        for(i = 0; i < imax; i ++)
            fprintf(outf, "%d\n", x[i]);

        fclose(outf);

        return 0;
    }

And I get this output:

-1631034645
-1593702794
-1465300620
-1263094822
-919238029
-889150029
-826670576
-579609061
-569653113
-305140505
-216823425
-193439331
-167683147
-49487019
-45223520
271789961
275570429
444855014
559132135
612312607
664554739
677860351
1005278191
1031629361
1089012280
1115952521
1521112993
1530518916
1907515865
1931470931