知足常足,终身不辱。 月圆缺,水满溢,事情到了极致一定会遭受祸患,只有懂得知足,才是富足。
习题46
宏#define命令练习。
实现思路:
宏通过#define
命令定义,分为无参宏和带参宏,可以分别进行测试。这只是一种简单的字符串代换。
代码如下:
#include <stdio.h>
#define TRUE 1
#define FALSE 0
#define SQR(x) (x)*(x)
int main(){
int num, next = TRUE;
while(next){
printf("Please input a number:\n");
scanf("%d", &num);
printf("Square = %d\n", SQR(num));
if(num > 10){
next = FALSE;
}
}
return 0;
}
打印:
Please input a number:
1
Square = 1
Please input a number:
5
Square = 25
Please input a number:
9
Square = 81
Please input a number:
13
Square = 169
习题47
宏#define命令练习,替换一个代码块。
实现思路: 实现在代码中使用宏就像调用函数一样(当然,实际上并不是调用函数)。
代码如下:
#include<stdio.h>
#define EXCHANGE(a,b) { int t;t=a;a=b;b=t;}
int main()
{
int x = 12;
int y = 20;
printf("Before Exchange:x=%d; y=%d\n",x,y);
EXCHANGE(x,y);
printf("After Exchange:x=%d; y=%d\n",x,y);
return 0;
}
打印:
Before Exchange:x=12; y=20
After Exchange:x=20; y=12
习题48
宏#define命令练习,替换运算符号。
实现思路: 在进行比较运算的时候用定义的宏替换掉原来的符号。
代码如下:
#include <stdio.h>
#define GT >
#define LT <
#define EQ ==
int main()
{
int i, j;
printf("Please input two numbers:\n");
scanf("%d %d", &i, &j);
if(i GT j)
printf("%d is greater than %d \n", i, j);
else if(i EQ j)
printf("%d is equal to %d \n", i, j);
else if(i LT j)
printf("%d is smaller than %d \n", i, j);
else
printf("Error\n");
return 0;
}
打印:
Please input two numbers:
13 45
13 is smaller than 45
习题49
#if、#ifdef和#ifndef的综合应用。
实现思路: 预处理程序提供了条件编译的功能,可以按不同的条件去编译不同的程序部分,因而产生不同的目标代码文件。
代码如下:
#include<stdio.h>
#define MAX
#define MAXIMUM(x,y) (x>y)?x:y
#define MINIMUM(x,y) (x>y)?y:x
int main(){
int a=12, b=20;
#ifdef MAX
printf("%d is bigger\n", MAXIMUM(a,b));
#else
printf("%d is smaller\n", MINIMUM(a,b));
#endif
#ifndef MIN
printf("%d is smaller\n", MINIMUM(a,b));
#else
printf("%d is bigger\n", MAXIMUM(a,b));
#endif
#undef MAX
#ifdef MAX
printf("%d is bigger\n", MAXIMUM(a,b));
#else
printf("%d is smaller\n", MINIMUM(a,b));
#endif
#define MIN 1
#ifndef MIN
printf("%d is smaller\n", MINIMUM(a,b));
#else
printf("%d is bigger\n", MAXIMUM(a,b));
#endif
#if(MIN)
printf("%d is smaller\n", MINIMUM(a,b));
#else
printf("%d is bigger\n", MAXIMUM(a,b));
#endif
return 0;
}
打印:
20 is bigger
12 is smaller
12 is smaller
20 is bigger
20 is bigger
习题50
#include的应用练习。
实现思路: 文件包含使用尖括号表示在包含文件目录中去查找(包含目录是由用户在配置环境时设置的),而不在源文件目录去查找; 使用双引号则表示首先在当前的源文件目录中查找,若未找到才到包含目录中去查找。
创建cp.h如下:
#define GT >
#define LT <
#define EQ ==
代码如下:
#include <stdio.h>
#include "cp.h"
int main()
{
int i, j;
printf("Please input two numbers:\n");
scanf("%d %d", &i, &j);
if(i GT j)
printf("%d is greater than %d \n", i, j);
else if(i EQ j)
printf("%d is equal to %d \n", i, j);
else if(i LT j)
printf("%d is smaller than %d \n", i, j);
else
printf("Error\n");
return 0;
}
打印:
Please input two numbers:
12 20
12 is smaller than 20
本文原文首发来自博客专栏C语言实战,由本人转发至https://www.helloworld.net/p/K2DS5af3lHmw,其他平台均属侵权,可点击https://blog.csdn.net/CUFEECR/article/details/106917485查看原文,也可点击https://blog.csdn.net/CUFEECR浏览更多优质原创内容。