wc命令的C语言实现

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该程序实现了wc的 -l -m -c -L -w这五个参数的（可组合使用）功能，首先关于其参数man的定义如下：

-c, --bytes  print the byte counts//字节数 -m, --chars print the character counts//字符数-l, --lines print the newline counts//行数-L, --max-line-length print the length of the longest line//最大行长度 -w, --words print the word counts //单词数
源代码如下：

#include<stdio.h>#include<unistd.h>#include<sys/stat.h>#include<stdlib.h>struct message{int lines;int words;int max_line_length;int size;int chars;}info;void error_print(char str[]){printf("Error:%s",str);}void init(char filename[]){struct stat get_message = {};FILE *fp;int ret_stat = stat(filename,&get_message);/*用stat函数读取filenmae文件的信息，并将结果写到get_message结构体中*/if(ret_stat == -1){//stat函数不出错则进行信息输出error_print(filename);return ;}mode_t mode = get_message.st_mode;//接收文件信息，用于下面判断是不是目录int length = 0;if(S_ISDIR(mode))//如果是目录，输出错误printf("Error %s is dir\n0\t0\t0\t%s",filename,filename);else{info.size = get_message.st_size;//文件字节大小 wc -cfp = fopen(filename,"r");//以只读方式打开指定文件char ch;int flag = 0;while((ch = fgetc(fp))!=EOF){//一直读到文件尾info.chars++;//字符数加1 wc -mif(ch != '\n'){length++;//记录当前行的长度 wc -L}if(ch == '\n'){info.lines ++;//行数加1 wc -lif(length>info.max_line_length)info.max_line_length = length;//更新最大长度length = 0;}if(ch == '\t' || ch == ' ' || ch == '\n'){flag = 0;//计算单词数 wc -wcontinue;}else{if(flag == 0){info.words++;//计算单词数 wc -wflag = 1;}}}fclose(fp);}}//计算键盘输入内容的相关信息，即参数中没有指定要打开的文件void EmptyFile(){char ch;int flag = 0;int length = 0;while((ch = getchar())!=EOF){info.chars++;info.size += sizeof(ch);//字节累加if(ch != '\n'){length++;}if(ch == '\n'){info.lines ++;if(length>info.max_line_length)info.max_line_length = length;length = 0;}if(ch == '\t' || ch == ' ' || ch == '\n'){flag = 0;continue;}else{if(flag == 0){info.words++;flag = 1;}}}}int main(int argc,char *argv[]){if(argc == 2){if(argv[1][0] != '-'){init(argv[1]);printf("%d %d %d %s\n",info.lines,info.words,info.size,argv[1]);return 0;}else{//未指定打开文件，类似 wc -lmwcLEmptyFile();}}else if(argc == 1){//未指定打开文件和要输出的参数，（默认输出 -lwc）EmptyFile();printf("%d\t%d\t%d\n",info.lines,info.words,info.size);return 0;}else if(argc == 3){init(argv[2]);}int num;while((num = getopt(argc,argv,"lwmcL"))!=-1){switch(num){case 'l':printf("%d\t",info.lines);break;case 'w':printf("%d\t",info.words);break;case 'm':printf("%d\t",info.chars);break;case 'c':printf("%d\t",info.size);break;case 'L':printf("%d\t",info.max_line_length);break;}}if(argc != 2 && argv[1][0] != '-')//一定要判断，否则会越界printf("%s\n",argv[2]);return 0;}

运行结果如下：

如果对文件进行操作，在参数选项后面加上文件名即可，注意要加绝对路径

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