#include <stdio.h>
#include <stdlib.h>

int Change(int &x, int &y);

int main()
{
    printf("Hello world!\n");
    int a, b;
    a = 1;
    b = 2;
    Change(a, b);
    printf("x: %d  \ny: %d", a, b);
    return 0;
}

int Change(int &x, int &y)
{
 int t;
 t = x;
 x = y;
 y = t;
 return 1;
}

||=== Build: Debug in Algorithms (compiler: GNU GCC Compiler) ===|
C:\a\Algorithms\main.c|4|error: expected ';', ',' or ')' before '&' token|
C:\a\Algorithms\main.c||In function 'main':|
C:\a\Algorithms\main.c|12|warning: implicit declaration of function 'Change' [-Wimplicit-function-declaration]|
C:\a\Algorithms\main.c|17|error: expected ';', ',' or ')' before '&' token|
||=== Build failed: 2 error(s), 1 warning(s) (0 minute(s), 0 second(s)) ===|