CODEWITHSUNDEEP
c++bit
Iurie Cojocari
Iurie Cojocari

Reputation: 17

set member of array to zero

Morning, I hope somebody is here suppose I have the following structure or even better an array of structures

struct foo {
  int a;
  char b[10];
  char c;
};

struct foo* bar;
bar = (struct foo*) malloc(sizeof(struct foo)*10);
memset(bar, -1, sizeof(struct foo)*10);

instead of 

for (counter = 0; counter < 10; ++counter)
      memset(bar[counter],0,sizeof(char)*10);

how to a set b member to 0 in all array of char / b member in all array?

basically my question is a bit similar to this one

Upvotes: 0

Views: 136

Answers (2)

IanM_Matrix1
IanM_Matrix1

Reputation: 1594

I'd like to suggest that rather than using a C-style array of int b[10]; that you use std::array<char,10> b; instead.

Then you can fill it with zeros this way: b.fill(0);. If you need to pass the address of the storage to a C-style function you can do that using b.data(). And of course, you can still access its content using b[i], but if you want more safety, use b.at(i).

http://en.cppreference.com/w/cpp/container/array

Upvotes: 1

Stack Exchange Broke The Law
Stack Exchange Broke The Law

Reputation: 58947

You can set the b member of each array element to zero by setting the b member of each array element to zero. You were almost there, but:

  1. You only wanted to zero the b member.
  2. The thing you're zeroing isn't 8 bytes long.

 

for (counter = 0; counter < 10; ++counter)
    memset(bar[counter].b, 0, sizeof bar[counter].b);

Upvotes: 0

Related Questions