gistfile1.c

// 变量的作用域


#include <stdio.h>
int count;  // this is a global variable

void head1();
void head2();
void head3();

void main()
{
	int index;   // this variable is available only in main
	head1();
	head2();
	head3();
	//  main "for" loop of this program
	for(index = 8; index > 0; index--)
	{
		int stuff;  // this variable is only available in these braces
		for(stuff = 0; stuff <= 6; stuff++)
		{
			printf("%d", stuff);
		}
		printf("index is now %d\n", index);
	}
}
int counter;   //this is available from this point on
void head1()
{
	int index;  // this variable is available only in head1
	index = 23;
	printf("The header1 value is %d\n", index);
}
void head2()
{
	int count;  //this variable is available only in head2
	//  and it displaces the global of the same name
	count = 53;
	printf("The header2 value is %d\n", count);
}
void head3()
{
	printf("The header3 value is %d\n", counter);
}