‘npos’ is not a member of ‘std’
#include <iostream>
#include <string>
int main() {
std::string str = "Hello, World!";
size_t found = str.find("abc");
if (found != std::string::npos) {
std::cout << "Substring found at position " << found << std::endl;
} else {
std::cout << "Substring not found" << std::endl;
}
return 0;
}