Coin Toss program not working Visual Studio 2010

Question

A book exercise prompts me to create a program that simulates coin tossing. My friend says he ran my code in a native GNU compiler, and it worked, but I'm receiving the following errors when I try to run it in Visual Studio 2010:

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

int result;

int flip();

int main(void)
{
    srand(time(NULL));

    int heads = 0;
    int tails = 0;
    unsigned counter;

    for(counter = 1; counter <= 100; counter++)
    {
        result = flip();

        if(result == 1)
        {
            printf("Heads\n");
            heads++;
        }

        else
        {
            printf("Tails\n");
            tails++;
        }
    }

        printf("Heads: %d\tTails: %d\n", heads, tails);
}

int flip()
{
    result = 1 + rand() % 2;

    if (result == 1)
        return 1;

    if (result == 2)
        return 0;

    return NULL;
}

---

syntax error: ')' (line 10)

'counter': undeclared identifier (15, 23)

'heads': undeclared identifier (19, 23)

't': undeclared identifier (10, 10)

syntax error: missing ')' before 'type' (line 10)

syntax error: missing ';' before '{' (line 11)

syntax error: missing ';' before 'type' (9, 10, 10, 10)

---

Thanks for any response.

Answer 1

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

int result;

int flip();

int main(void){
    int heads = 0;
    int tails = 0;
    unsigned counter;

    srand(time(NULL));//Executable statement after the declaration

    for(counter = 1; counter <= 100; counter++){
        result = flip();

        if(result == 1){
            printf("Heads\n");
            heads++;
        } else {
            printf("Tails\n");
            tails++;
        }
    }

    printf("Heads: %d\tTails: %d\n", heads, tails);
    return 0;
}

int flip() {
    result = 1 + rand() % 2;

    return result == 1;
}