1.纯C实现:
FILE *fp; if ((fp = fopen("example.txt", "rb")) == NULL) { exit(0); } fseek(fp, 0, SEEK_END); int fileLen = ftell(fp); char *tmp = (char *) malloc(sizeof(char) * fileLen); fseek(fp, 0, SEEK_SET); fread(tmp, fileLen, sizeof(char), fp); fclose(fp); for(int i = 0; i < fileLen; ++i) { printf("%d ", tmp[i]); } printf("\n"); if ((fp = fopen("example.txt", "wb")) == NULL) { exit(0); } rewind(fp); fwrite(tmp, fileLen, sizeof(char), fp); fclose(fp); free(tmp);
2.利用CFile(MFC基类)
CFile需要包含的头文件为Afx.h
打开文件的函数原型如下
if(!(fp.Open((LPCTSTR)m_strsendFilePathName,CFile::modeRead)))
有多种模式,常用的有如下:
modeRead
modeWrite
modeReadWrite
modeCreate
文件类型有两种:
typeBinary
typeText
读写非文本文件一定要用typeBinary
读取数据的函数原型:
virtual UINT Read(void*lpbuf, UINT nCount);
代码:
//将文件读出 CFile fp; if(!(fp.Open((LPCTSTR)m_strsendFilePathName,CFile::modeRead))) { return; } fp.SeekToEnd(); unsignedint fpLength = fp.GetLength(); char *tmp= new char[fpLength]; fp.SeekToBegin(); //这一句必不可少 if(fp.Read(tmp,fpLength) < 1) { fp.Close(); return; } // 新建文件并写入 if(!(fp.Open((LPCTSTR)m_strsendFilePathName,CFile::modeCreate | CFile::modeWrite |CFile::typeBinary))) { return; } fp.SeekToBegin(); fp.write(tmp,fpLength); fp.close;
#include <stdio.h> #include <string.h> #define MAXLEN 10240 //读取文件filename的内容到dest数组,最多可以读maxlen个字节 //成功返回文件的字节数,失败返回-1 int read_file(const char *filename, char *dest, int maxlen) { FILE *file; int pos, temp, i; //打开文件 file = fopen(filename, "r"); if( NULL == file ) { fprintf(stderr, "open %s error\n", filename); return -1; } pos = 0; //循环读取文件中的内容 for(i=0; i<MAXLEN-1; i++) { temp = fgetc(file); if( EOF == temp ) break; dest[pos++] = temp; } //关闭文件 fclose(file); //在数组末尾加0 dest[pos] = 0; return pos; } int main(int argc, char **argv) { if( argc != 2 ) { fprintf(stderr, "Using: ./read <filename>\n"); return -1; } char buffer[MAXLEN]; int len = read_file(argv[1], buffer, MAXLEN); //输出文件内容 printf("len: %d\ncontent: \n%s\n", len, buffer); return 0; }