Loop Iteration Efficient

You have a loop that iterates over 1,000 i开发者_运维百科tems. You want to add a newline to every four items. The items are in an array structure that have numeric index starting at 0. How do you do it?

FWIW:

for (int i = 0; i < list.size(); ++i) {
    // you want to 'do it' with list[i] here

    if (0 == (i+1)%4))
    {
           // 'you want to add a new line' here
    }
}

Just in case what you are really trying to ask is "How do I print these items, four to a line?" here's one way

int nOnLine = 0;
for (i = 0; i < 1000; i++){
  // print item i
  nOnLine++;
  if (nOnLine >= 4){
    // print newline
    nOnLine = 0;
  }
}
if (nOnLine > 0){
  // print newline
  nOnLine = 0;
}

for (int i = 0; i < list.size(); i += 4) {
 // add to the item
}

The above iterates over every fourth item instead of every single item.

for(i=3;i<len;i=i+4) { // where len is the length of your array
  ary[i]+='\n';        // use string append operator of your language.
}

which will add a newline to every fourth item, i.e. items 3, 7, 11, etc.

EDIT

Changed to fulfill the OP's criteria.