Class T1 is type of sum of array elements

template<class T, class T1>

class array{

public:

array(int size);

T1 sum(void);

T average_value(void);

void show_array(void);

int add_value(T);

private:

T *data;

int size;

int index;};

template<class T, class T1>

T1 array<T, T1>:sum(void)

{

T1 sum = 0; int i;

for (i = 0; i < index; i++)

sum += data[i];

return(sum);}