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C++ Quiz #129

The Error That Waits for Instantiation

hardTemplates

Without the larger(p, q) line the program compiles and prints 9. Adding that line makes the build fail. Why?

📄 Code

1#include <iostream>
2 
3template <typename T>
4T larger(T a, T b) {
5    if (a < b) {
6        return b;
7    }
8    return a;
9}
10 
11struct Point {
12    int x;
13    int y;
14};
15 
16int main() {
17    std::cout << larger(3, 9) << "\n";
18    Point p{1, 2};
19    Point q{3, 4};
20    Point r = larger(p, q);   // this line breaks the build
21    std::cout << r.x << "\n";
22    return 0;
23}