#include指令要点

最新推荐文章于 2022-06-08 17:34:04 发布

12小白

最新推荐文章于 2022-06-08 17:34:04 发布

阅读量800

点赞数

CC 4.0 BY-SA版权

分类专栏： c 文章标签： #include指令

本文链接：https://blog.youkuaiyun.com/u012270113/article/details/30035095

c 专栏收录该内容

2 篇文章

订阅专栏

1.使用#include 指令避免重复声明

一段代码longest.c，代码内容忽略不看

longest.c

#include <stdio.h>
#include <stdlib.h>
#define MAX_LEN 1001 /* Buffer size for longest line */
#include <string.h> 

/*
** Reads lines of input from the standard input and prints the longest line that
** was found to the standard output. It is assumed that no line will exceed** 1000 characters.
*/

int main( void )
{
	freopen("in.txt","r",stdin);
    freopen("out.txt","w",stdout);
char input[ MAX_LEN ];
int len;
char longest[ MAX_LEN ];
int longest_len;
/*
** Initialize length of the longest line found so far.
*/
longest_len = -1;
/*
** Read input lines, one by one.
*/
while( gets( input ) != NULL ){
/*
** Get length of this line. If it is longer than the previous
** longest line, save this line.
*/
len = strlen( input );
if( len > longest_len ){
longest_len = len;
strcpy( longest, input );
}
}
/*
** If we saved any line at all from the input, print it now.
*/
if( longest_len >= 0 )
puts( longest );
return EXIT_SUCCESS;
}

可以改变成下面两个源文件util.cpp和longest.c.

util.cpp

#include <stdio.h>

#include <stdlib.h>
#define MAX_LEN 1001 /* Buffer size for longest line */
#include <string.h>

longest.c

/*
** Reads lines of input from the standard input and prints the longest line that
** was found to the standard output. It is assumed that no line will exceed** 1000 characters.
*/
#include "util.cpp"
int
main( void )
{
	freopen("in.txt","r",stdin);
    freopen("out.txt","w",stdout);
char input[ MAX_LEN ];
int len;
char longest[ MAX_LEN ];
int longest_len;
/*
** Initialize length of the longest line found so far.
*/
longest_len = -1;
/*
** Read input lines, one by one.
*/
while( gets( input ) != NULL ){
/*
** Get length of this line. If it is longer than the previous
** longest line, save this line.
*/
len = strlen( input );
if( len > longest_len ){
longest_len = len;
strcpy( longest, input );
}
}
/*
** If we saved any line at all from the input, print it now.
*/
if( longest_len >= 0 )
puts( longest );
return EXIT_SUCCESS;
}

2.在#include文件中放置函数原型

原来的代码binaryTree.cpp如下：

#include<iostream>
#include "find.cpp"
#include "res.cpp"
using namespace std;
#define N 201
int n,m,pre[N];
bool useif[N],map[N][N];
bool find(int x);
int res();
int main()
{
    freopen("in.txt","r",stdin);
    freopen("out.txt","w",stdout);
    int i,j,num,t;
    while(scanf("%d%d",&n,&m)!=EOF)
    {
        memset(map,0,sizeof(map));
        for(i=1;i<=n;i++)
        {
        scanf("%d",&num);
        for(j=1;j<=num;j++)
        {scanf("%d",&t);map[i][t]=1;}
        }
        int ans=res();
        cout<<ans<<endl;
    }
        return 0;
}

bool find(int x)
{
	int m=0;
    int k;
    for(k=1;k<=m;k++)
    {
        if(!useif[k]&&map[x][k])
        {
            useif[k]=1;
            if(pre[k]==-1||find(pre[k]))
            {
                pre[k]=x;
                return 1;
            }
            
        }
    }
        return 0;
}

int res()
{
    int count=0;
    memset(pre,-1,sizeof(pre));
    for(int i=1;i<=n;i++)
    {
        memset(useif,0,sizeof(useif));
        if(find(i))
        count ++;
    }
        return count;
}

此时，把一个源文件转换为三个文件

find.cpp

bool find(int x)
{
	int m=0;
    int k;
    //for(k=1;k<=m;k++)
//    {
//        if(!useif[k]&&map[x][k])
//        {
//            useif[k]=1;
//            if(pre[k]==-1||find(pre[k]))
//            {
//                pre[k]=x;
//                return 1;
//            }
//            
//        }
//    }
        return 0;
}

res.cpp

bool find(int x)
{
	int m=0;
    int k;
    //for(k=1;k<=m;k++)
//    {
//        if(!useif[k]&&map[x][k])
//        {
//            useif[k]=1;
//            if(pre[k]==-1||find(pre[k]))
//            {
//                pre[k]=x;
//                return 1;
//            }
//            
//        }
//    }
        return 0;
}

binaryTree.cpp

#include<iostream>
#include "find.cpp"
#include "res.cpp"
using namespace std;
#define N 201
int n,m,pre[N];
bool useif[N],map[N][N];

int main()
{
    freopen("in.txt","r",stdin);
    freopen("out.txt","w",stdout);
    int i,j,num,t;
    while(scanf("%d%d",&n,&m)!=EOF)
    {
        memset(map,0,sizeof(map));
        for(i=1;i<=n;i++)
        {
        scanf("%d",&num);
        for(j=1;j<=num;j++)
        {scanf("%d",&t);map[i][t]=1;}
        }
        int ans=res();
        cout<<ans<<endl;
    }
        return 0;
}