#include <stdio.h> #include <stdlib.h> #include <string.h> int merge(int* ar1, int len1, int* ar2, int len2, int** rtn) /*++  DeScription:     This routine merge two sorted arrays into one sorted array,     the same values in different arrays will be keeped. Arguments:     ar1 - The first sorted array to be merged     len1 - The num of items in ar1     ar2 - The second sorted array to be merged     len2 - The num of items in ar2     rtn - The caller proviced pointer to get the result array,         memory allocated for rtn should be free by the caller. Return Value:     The num of items in the merge array --*/ {     int i=0,j=0,k=0;     int m=0;     int* res = NULL;     if (ar1 == NULL || ar2 == NULL || rtn == NULL) {         return 0;     }     *rtn = (int *)malloc((len1+len2)*sizeof(int));     if(*rtn == NULL) {         return 0;     }     memset(*rtn, 0, (len1+len2)*sizeof(int));     res = (int*)*rtn;     while(i<len1 && j<len2) {         if (ar1[i]<=ar2[j]) {             res[k++] = ar1[i++];         } else {             res[k++] = ar2[j++];         }     }     while(i<len1) {         res[k++] = ar1[i++];     }     while(j<len2) {         res[k++] = ar2[j++];     }     return  len1+len2; } int merge_test() {     int a1[] = {0,1,2,5,8,19,34,43,52};     int a2[] = {1,4,5,12,17,33,42,51,53,65,76};     int len1 = sizeof(a1)/sizeof(int);     int len2 = sizeof(a2)/sizeof(int);     int i = 0, len = 0;     int* a3 = NULL;     int* ptr = NULL;     len = merge(a1, len1, a2, len2, &a3);     if (a3 == NULL) {         printf("a3==NULL\n");         return 1;     }     ptr = a3;     while(i<len) {         printf("a3[%3d]---->%8d\n", i++, *ptr++);        }     if (a3 != NULL) {         free(a3);     }     return 0; } int main(int argc, char* argv[]) {     merge_test();     return 0; }