Range-Based For Loop (For-Each)

Range-Based For Loop (For-Each)

The range-based for loop visits every element of a collection without counting indexes. C++ does the bookkeeping for you.

The shape

for (type item : collection) {
  // use item
}

• type is the type of one element.
• item is a new variable that holds each element in turn.
• collection is the thing to walk through.
• The loop runs the body once per element.

A vector example

#include <iostream>
#include <vector>
using namespace std;

int main() {
  vector<int> nums = {10, 20, 30};
  for (int num : nums) {
    cout << num << endl;
  }
  return 0;
}

The loop prints 10, 20, 30. No indexes, no i < size, no off-by-one mistakes.

It works on arrays and strings too

The same loop handles plain arrays and std::string:

int scores[] = {90, 80, 70};
for (int s : scores) {
  cout << s << " ";
}

string word = "hey";
for (char c : word) {
  cout << c << " ";
}

For a string, each element is a single character.

TL;DR

• for (type item : collection) visits each element in order.
• No index or size is needed; C++ handles the range.
• It works with arrays, vectors, and strings.
• In a string, each item is one character.