Initializing entire array with memset

Question

I have initialised the entire array with value 1 but the output is showing some garbage value. But this program works correctly if i use 0 or -1 in place of 1. So are there

Answer 1

The other answers have explained std::memset already. But it's best to avoid such low level features and program at a higher level. So just use the Standard Library and its C++11 std::array

#include 

std::array a;
a.fill(1);

Or if you prefer C-style arrays, still use the Standard Library with the std::fill algorithm as indicated by @BoPersson

#include 
#include 

int a[100];
std::fill(std::begin(a), std::end(a), 1);

In most implementations, both versions will call std::memset if it is safe to do so.