#include<stdio.h>
varfunc()
{
int var=0;
static int static_var=0;
printf("\40:var equal %d \n",var);
printf("\40:static var equal %d \n",static_var);
printf("\n");
var++;
static_var++;
}
viod main()
{int i;
for(i=0;i<3;i++)
varfunc();
}
-----------------------------------------------------------------------------
【程序42】：学习使用auto定义变量的用法
1.程序分析：
2.程序源代码：
#inclu
de<stdio.h>
viod main()
{int i,num;
num=2;
for (i=0;i<3;i++)
{ printf("\40: The num equal %d \n",num);
num++;
{
auto int num=1;
printf("\40: The internal block num equal %d \n",num);
num++;
}
}
}
-----------------------------------------------------------------------------
【程序43】：学习使用static的另一用法。
1.程序分析：
2.程序源代码：
#include<stdio.h>
viod main()
{
int i,num;
num=2;
for(i=0;i<3;i++)
{
printf("\40: The num equal %d \n",num);
num++;
{
static int num=1;
printf("\40:The internal block num equal %d\n",num);
num++;
}
}
}
-----------------------------------------------------------------------------
【程序44】：学习使用external的用法。
1.程序分析：
2.程序源代码：
#include<stdio.h>
int a,b,c;
void add()
{ int a;
a=3;
c=a+b;
}
viod main()
{ a=b=4;
add();
printf("The value of c is equal to %d\n",c);
}
-----------------------------------------------------------------------------
【程序45】：学习使用register定义变量的方法。
1.程序分析：
2.程序源代码：
void #include<stdio.h>
viod main()
{
register int i;
int tmp=0;
for(i=1;i<=100;i++)
tmp+=i;
printf("The sum is %d\n",tmp);
}
-----------------------------------------------------------------------------
【程序46】：宏#define命令练习(1)
1.程序分析：
2.程序源代码：
#include <stdio.h>
#define TRUE 1
#define FALSE 0
#define SQ(x) (x)*(x)
viod main()
{
int num;
int again=1;
printf("\40: Program will stop if input value less than 50.\n");
while(again)
{
printf("\40:Please input number==>");
scanf("%d",&num);
printf("\40:The square for this number is %d \n",SQ(num));
if(num>=50)
again=TRUE;
else
again=FALSE;
}
}
-----------------------------------------------------------------------------
【程序47】：宏#define命令练习(2)
1.程序分析：
2.程序源代码：
#include<stdio.h>
#define exchange(a,b) { \ /*宏定义中允许包含两道衣裳命令的情形，此时必须在最右边加上"\"*/
int t;\
t=a;\
a=b;\
b=t;\
}
void main(void)
{
int x=10;
int y=20;
printf("x=%d; y=%d\n",x,y);
exchange(x,y);
printf("x=%d; y=%d\n",x,y);
}
-----------------------------------------------------------------------------
【程序48】：宏#define命令练习(3)
1.程序分析：
2.程序源代码：
#define LAG >
#define SMA <
#define EQ ==
#include<stdio.h>
viod main()
{ int i=10;
int j=20;
if(i LAG j)
printf("\40: %d larger than %d \n",i,j);
else if(i EQ j)
printf("\40: %d equal to %d \n",i,j);
else if(i SMA j)
printf("\40:%d smaller than %d \n",i,j);
else
printf(&q
uot;\40: No such value.\n");
}
-----------------------------------------------------------------------------
【程序49】：#if #ifdef和#ifndef的综
合应用。
1. 程序分析：
2.程序源代码：
#include <stdio.h>
#define MAX
#define MAXIMUM(x,y) (x>y)?x:y
#define MINIMUM(x,y) (x>y)?y:x
viod main()
{ int a=10,b=20;
#ifdef MAX
printf("\40: The larger one is %d\n",MAXIMUM(a,b));
#else
printf("\40: The lower one is %d\n",MINIMUM(a,b));
#endif
#ifndef MIN
printf("\40: The lower one is %d\n",MINIMUM(a,b));
#else
printf("\40: The larger one is %d\n",MAXIMUM(a,b));
#endif
#undef MAX
#ifdef MAX
printf("\40: The larger one is %d\n",MAXIMUM(a,b));
#else
printf("\40: The lower one is %d\n",MINIMUM(a,b));
#endif
#define MIN
#ifndef MIN
printf("\40: The lower one is %d\n",MINIMUM(a,b));
#else
printf("\40: The larger one is %d\n",MAXIMUM(a,b));