# V770\. Possible use of left shift operator instead of comparison operator\.

The analyzer detected a potential typo that deals with using operators '<<' and '<<\=' instead of '<' and '<\=', respectively, in a loop condition\.

Consider the following example:

```cpp
void Foo(std::vector<int> vec)
{
  for (size_t i = 0; i << vec.size(); i++) // <=
  {
    // Something
  }
}
```

The "i << vec\.size\(\)" expression evaluates to zero, which is obviously an error because the loop body will not execute even once\. Fixed code:

```cpp
void Foo(std::vector<int> vec)
{
  for (size_t i = 0; i < vec.size(); i++) 
  {
    // Something
  }
}
```

Note\. Using right\-shift operations \(\>\>, \>\>\=\) is considered a normal situation, as they are used in various algorithms, for example computing the number of bits with the value 1, for example:

```cpp
size_t num;
unsigned short var = N;
for (num = var & 1 ; var >>= 1; num += var & 1);
```