#includeIn the first example, a TString object is created with the value "123". The Atoi function is called on this object, which returns the integer value 123. This value is then outputted to the console. In the second example, the TString object has a hexadecimal value "0x42". The Atoi function is called with a parameter of 16, indicating that the string should be interpreted as a hexadecimal value. The resulting integer value of 66 (hexadecimal 42) is then outputted to the console. In the third example, a negative integer string "-456" is converted to an integer value using the Atoi function. The resulting integer value of -456 is then outputted to the console. The TString class and its associated functions are part of the ROOT package in C++.#include int main() { TString str = "123"; int num = str.Atoi(); std::cout << num << std::endl; // outputs "123" TString hex = "0x42"; int hex_num = hex.Atoi(16); std::cout << std::hex << hex_num << std::endl; // outputs "42" TString neg = "-456"; int neg_num = neg.Atoi(); std::cout << neg_num << std::endl; // outputs "-456" return 0; }