How do I concatenate the string elements of my array into a single string in C? -

i have array of strings , create new string concatenation of array elements. appreciated, thanks

#include <stdio.h> #include <stdlib.h> #include <string.h>  char *concatenate(size_t size, char *array[size], const char *joint){     size_t jlen, lens[size];     size_t i, total_size = (size-1) * (jlen=strlen(joint)) + 1;     char *result, *p;       for(i=0;i<size;++i){         total_size += (lens[i]=strlen(array[i]));     }     p = result = malloc(total_size);     for(i=0;i<size;++i){         memcpy(p, array[i], lens[i]);         p += lens[i];         if(i<size-1){             memcpy(p, joint, jlen);             p += jlen;         }     }     *p = '\0';     return result; }  int main(){     char *ss[] = { "first", "second", "last" };     char *cat = concatenate(3, ss, "");     puts(cat);     free(cat);     cat = concatenate(3, ss, ", ");     puts(cat);     free(cat);     return 0; }