In C++, std::string is a class that represents a sequence of characters. It is much more powerful and safer than C-style character arrays (char*).

For any text processing, string concatenation, searching, and manipulation.

• Access: $O(1)$
• Concatenation: $O(N+M)$
• Length: $O(1)$
• Search: $O(N)$

cpp Standard
#include <string>

std::string s = "Hello";
s += " World"; // Concatenation
int len = s.length(); // 11
char first = s[0]; // 'H'

• Using == to compare C-style strings (use strcmp) vs std::string (where == works perfectly).
• Accessing indices out of bounds using [] (doesn't throw exception) instead of .at() (throws exception).
• Inefficient string concatenation in loops (creates many temporary objects).