C++ 中未解决的外部问题

Question

#include <iostream>
using namespace std;

void PrintN(int i, int N)
{
    for (i = 1; i <= N; i++)
        printf("%d\n", i);
    return;
}

when I compiled it, it worked well, but it gave two errors in line 1 when I built it. One is "Error LNK2019 unresolved external symbol _main referenced in function "int __cdecl invoke_main(void)" (?invoke_main@@YAHXZ)" The other is "unresolved externals". But after I add "int main()", it can work well,but not export the integers from 1 to N on the screen. I think the void function can work independently even without main function. It really made me confused.

Answer 1

You need to define main , without it the OS has no way to execute your application. Furthermore, who would execute PrintN ?

#include <iostream>

void PrintN( int i, int n )
{
    for (; i < n; i++ )
        std::cout << i << '\n';
}

int main( )
{
    PrintN( 10, 20 ); 
}