#include <stdio.h>
    #include <string.h>
 
    #define MAXVAL 50
 
    unsigned int CountDistinctsElements(unsigned int* iArray, unsigned int iNbElem) {
      unsigned int ret = 0;
 
      //this array will contains the count of each value
      //for example, c[3] will contain the count of the value 3 in your original array
      unsigned int c[MAXVAL];
      memset(c, 0, MAXVAL*sizeof(unsigned int));
 
      for (unsigned int i=0; i<iNbElem; i++) {
        unsigned int elem = iArray[i];
        if (elem < MAXVAL && c[elem] == 0) {
          ret++;
        }
        c[elem]++;
      }
      return ret;
    }
 
    int main() {
      unsigned int myElements[10] = {0, 25, 42, 42, 1, 2, 42, 0, 24, 24};
      printf("Distincts elements : %d\n", CountDistinctsElements(myElements, 10));
      return 0;
    }

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