このプログラム何がおかしいんですか？
#include<stdio.h>
void func1(int x, int y);
int func2;
void func3(int x, int y);
void func4(int *p, int *q);
void func5(int x);
int a = 1, b =2;
main()
{
int a = 3, c = 4;
printf("in main a = %d\n",a);
printf("in main b = %d\n",b);
printf("in main c = %d\n",c);
func1(++c, b);
a = func2();
func3(a,c);
printf("in main2 a = %d\n",a);
printf("in main2 b = %d\n",b);
printf("in main2 c = %d\n",c);
b = func4(&a, &c);
printf("in main3 a = %d\n",a);
printf("in main3 b = %d\n",b);
printf("in main3 c = %d\n",c);
func5(a);
}