/*** copy new_val in the array at index v->no_e ***/
void v_push_back(vector_type v, void* new_val){
if( v->no_e >= v->cur_cap ){
/*** reallocate a larger array ***/
v->cur_cap += (v->cur_cap) ? v->cur_cap : 2;
v->e_array = realloc(v->e_array, v->cur_cap*(v->e_sz))
}
/*** copy new_val in the array at index v->no_e ***/
/*** TO BE DONE START ***/
if(v->e_type == 1)
memcpy(((int*)v->e_array) + v->no_e*(v->e_sz), new_val, v->e_sz);
else if(v->e_type == 2)
memcpy(((double*)v->e_array) + v->no_e*(v->e_sz), new_val, v->e_sz);
else if(v->e_type == 3)
memcpy(((char*)v->e_array) + v->no_e*(v->e_sz), new_val, v->e_sz);
else if(v->e_type == 4)
memcpy(((float*)v->e_array) + v->no_e*(v->e_sz), new_val, v->e_sz);
/*** TO BE DONE END ***/
(v->no_e)++;
}