c - 将文本文件输出到屏幕

Question

我需要制作一个“搜索和替换”程序。它不必在输入文件中进行更改，而只需在屏幕上进行更改。

示例:

file: foo pap ran bar foo. Nam foo!

replace:  foo >with> bar

output to screen: bar pap ran bar bar. Nam bar!`

有人知道我该怎么做吗？我是 C 新手。

Answer 1

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

long GetFileSize(FILE *fp){
    long fsize = 0;

    fseek(fp,0,SEEK_END);
    fsize = ftell(fp); 
    fseek(fp,0,SEEK_SET);//reset stream position!!

    return fsize;
}

int main(int argc, char **argv){
    char *file, *sword, *rword, *buff, *wp,*bp;
    int len;
    long fsize;
    FILE *inpFile;

    if(argc != 4){
        fprintf(stderr, "Usage:rep filePath originalWord replaceWord\n");
        exit(EXIT_FAILURE);
    }
    file  = argv[1];
    sword = argv[2];
    rword = argv[3];
    if(NULL==(inpFile=fopen(file, "rb"))){
        perror("Can't open file");
        exit(EXIT_FAILURE);
    }
    fsize = GetFileSize(inpFile);
    buff=(char*)malloc(sizeof(char)*fsize+1);
    fread(buff, sizeof(char), fsize, inpFile);//file all read into buff
    fclose(inpFile);
    buff[fsize]='\0';
    bp=buff;
    len = strlen(sword);
    while(NULL!=(wp=strstr(bp, sword))){
        while(bp != wp)
            putchar(*bp++);
        printf("%s",rword);
        bp+=len;
    }
    if(bp) printf("%s", bp);
    free(buff);
    return 0;
}