代码:

---

#include <stdio.h>
#include <stdlib.h>

#define TXT_LENGTH 1024

int main(int argc, char *argv[]) {
	if (argc!=2) {
		printf("Command Usage: %s <filename>\n", argv[0]);
		exit(-1);
	}

	FILE *fileName;
	char *txtLine;

	if ((fileName=fopen(argv[1], "r"))==NULL) {
		printf("Open file %s failed.\n Exit program\n",argv[2]);
		exit(-1);
	}
	
	txtLine=malloc(TXT_LENGTH);
	char *head;
	head=txtLine;

	while (fgets(head, TXT_LENGTH, fileName)!=NULL) {
		txtLine=head;
		while (*txtLine++!='#')
			if (*txtLine=='\0') {
				printf("%s",head);
				break;
			}
	}
	free(head);
	exit (0);
}

---

代码:

---

#include <stdio.h>
#include <sys/types.h>
#include <sys/stat.h>

int main(int argc,char *argv[])
{
        int flen;
        FILE    *fp1,*fp2;
        struct stat *f_stat=(struct stat *)malloc(sizeof(struct stat));

        char *buf;
        int i;
        
        if(argc!=3) {
                printf("usage: %s sourcefile destfile\n",argv[0]);
                exit(0);
        }
        if((fp1=fopen(argv[1],"r"))==NULL)
        {
                perror("fopen");
                exit(0);
        }

        if((fp2=fopen(argv[2],"w"))==NULL)
        {
                perror("fopen");
                exit(0);
        }
        if(lstat(argv[1],f_stat)!=0 )
        {
                perror("fstat");
                exit(0);
        }

        flen=f_stat->st_size;
        buf=(char *)malloc(flen);

        while(fgets(buf,flen,fp1)!=NULL)
        {
                for(i=0;i<flen-1&&buf[i]==' ';i++) ;
                if(i!=flen-1 && buf[i]!='#' )
                {
                        fputs(buf,fp2);
                }
        }


        printf("Write succeed!\n");
        fclose(fp1);
        fclose(fp2);
        return 1;
}

---

引用:

---

[macavity@Macavity grep]$ ./a.out test.txt
1alskgd;alsdfkje;likajsldfkjelkjskdfjdkd
12
123
1234
123456
1234567
12345678
123456789
1234567890
123456789[macavity@Macavity grep]$ grep -v '#' test.txt
1alskgd;alsdfkje;likajsldfkjelkjskdfjdkd
12
123
1234
123456
1234567
12345678
123456789
1234567890
[macavity@Macavity grep]$
[macavity@Macavity grep]$ cat test.txt
#slkjdfe
1alskgd;alsdfkje;likajsldfkjelkjskdfjdkd
12
123
1234
123 #45
123456
1234567
12345678
123456789
1234567890
12345678901#
[macavity@Macavity grep]$

---

代码:

---

void ReadConfigFile (const char* fileName)
{
	int	c;
	char	*buf;
	size_t	len;
	char	*ptr, *p;
	char*	option;
	FILE *fp;
	fp = fopen(fileName,"r");
	if(fp == NULL){
		MakeConfigFile(fileName);
		/*perror("Read ConfigFile");*/
		exit (1);
	}
	while ((buf = fgetln(fp, &len)) != NULL) {
		if (buf[len - 1] == '\n')
			buf[len - 1] = '\0';
		else{
			perror("config file format error: "
				"last line should end with newline");
			exit(1);	
		}
/*
 * Check for comments, strip off trailing spaces.
 */
		if ((ptr = strchr(buf, '#')))
			*ptr = '\0';
		for (ptr = buf; isspace(*ptr); ++ptr)
			continue;
		if (*ptr == '\0')
			continue;
		for (p = strchr(buf, '\0'); isspace(*--p);)
			continue;
		*++p = '\0';

/*
 * Extract option name.
 */
		option = ptr;
		while (*ptr && !isspace (*ptr))
			++ptr;

		if (*ptr != '\0') {

			*ptr = '\0';
			++ptr;
		}
/*
 * Skip white space between name and parms.
 */
		while (*ptr && isspace (*ptr))
			++ptr;

		ParseOption (option, *ptr ? ptr : NULL);
	}
	fclose(fp);
}

---

代码:

---

		if ((ptr = strchr(buf, '#')))
			*ptr = '\0';]}

---

引用:

---

问题：
for (ptr = buf; isspace(*ptr); ++ptr)
        continue;
和
for (ptr = buf; isspace(*ptr); ++ptr);
是完全一样的吗？功能当然是一样的，我问得是执行的时候....you know

---

引用:

---

还有就是，一个char *，比如叫strPtr。那么
while(*++strPtr);
是个什么意思？一直不太明白。我觉得就是和下面这个是一样的：
while(*++strPtr!='\0');
但是我经常看见不一样的写法同时存在于一个程序里面，我就糊涂了

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