#include <stdio.h>
#include <stdlib.h>
#include <memory.h>
int cmpW( const void* p1, const void*p2){
     float *pf1 = (float*)p1;
     float *pf2 = (float*)p2;
     return pf1[0] - pf2[0];
}
int cmpH( const void* p1, const void*p2){
     float *pf1 = (float*)p1;
     float *pf2 = (float*)p2;
     return pf2[1] - pf1[1];
}

int main(void)
{
     const size_t n = 5;
     float A[n][2] = {0};
     int i=0;
     for(i=0; i<n; ++i){ // Data input.
     printf("W H: ");
     scanf("%f %f", &A[i][0], &A[i][1]);
     }
     qsort(A, n, sizeof(float) * 2, cmpW ); // By weight
     for(i=0; i<n; ++i) // Data input.
     printf("(%f, %f) ", A[i][0], A[i][1]);
     printf("n");
     qsort(A, n, sizeof(float) * 2, cmpH ); // By height
     for(i=0; i<n; ++i) // Data input.
     printf("(%f, %f) ", A[i][0], A[i][1]);
     printf("n");

    system("pause");
}