freplace.c

/* Author: bhw * EMail: [e-mail] * Date: 2009.03.04 22:22*/ /* *Function:Replace old_word in Src file with new_word,and save it as Des file */#include<stdio.h>#include<string.h>#define SIZE 256 //define buf size, 256 is big enough for common filesvoid freplace(char *p, FILE *fpDes, char *pargv3, char *pargv4);int main(int argc, char *argv[]){FILE *fpSrc,//src file *fpDes;//des filestatic char buf[SIZE];if(argc != 5){printf("Usage:%s [src file name] [des file name] [old word] [new word]/n", argv[0]);return 0;}//Make sure the src file and des file are legal to deal with.fpSrc = fopen(argv[1], "r"); if(fpSrc == NULL){perror("Open src file");return 0;}fpDes = fopen(argv[2], "w");if(fpDes == NULL){perror("Open des file");return 0;}while(fgets(buf, SIZE, fpSrc) != NULL) //get a line(ended with '/n') at one time and move it into buf{freplace(buf, fpDes, argv[3], argv[4]); //deal with buf}fclose(fpSrc);fclose(fpDes);return 0;}void freplace(char *p, FILE *fpDes, char *pargv3, char *pargv4){char word[SIZE], *pword;while((*p != '/n') && (*p != '/0')) //in buf,it seems like this:" abc def ghi;/n/0",{ //there is a '/n' because fgets() could accept '/n'.fgets() adds a '/0' in the end.while((*p == ' ') || (*p == '/t')) //at first deal with the spaces in buf{fputc(*p, fpDes); //output the spaces into des file++p;}for(pword=word; *p != ' ' && *p != '/t' && *p != '/n'; )//start record non-space characters{*pword++ = *p++; }*pword = '/0'; //a complete word string has been recorded.if(strcmp(word, pargv3) == 0) //compare word with old_word,if equal,output new_word into des filefprintf(fpDes, "%s", pargv4);elsefprintf(fpDes, "%s", word);//otherwise,output word into des file.}if(*p == '/n')//output the '/n' to end a linefputc('/n', fpDes);}