标签:lan event and utc size error sign success 文件复制
使用 C 语言标准库 <stdio.h> 中的 FILE 指针指向原文件和目标文件,然后调用函数 fgetc/fputc 或 fread/fwrite 实现从原文件到目标文件的字节复制。
int val = 0;
while ((val = fgetc(fpbr)) != EOF)
fputc(val, fpbw);
注:
1)EOF宏,表示文件尾(End Of File),定义在 <stdio.h> 头文件中,其值为 -1;
2)虽然 fgetc/fputc 函数的功能是从文件流中读/写一个字符,实际上字符使用的是 int 整型,不是 char 类型。如果使用 char 类型,可能会导致文件复制不全;
示例代码一
char ch;
while (fread(&ch, sizeof(char), 1, fpbr) != 0)
fwrite(&ch, sizeof(char), 1, fpbw);
示例代码二
size_t len = 0;
char buffer[BUFSIZ] = {‘\0‘}; // BUFSIZ macro defined in <stdio.h>
while ((len = fread(buffer, sizeof(char), BUFSIZ, fpbr)) > 0)
fwrite(buffer, sizeof(char), len, fpbw);
注:
1)BUFSIZ 是定义在头文件 <stdio.h> 中的宏,其值为 512;
2)fread/fwrite 函数的功能是从文件流中读/写块数据,其函数原型均为 size_t fread/fwrite ( void * ptr, size_t size, size_t count, FILE * stream ); 其中 ptr 为读写所用的元素数组指针; size 为用于读写的每个元素大小,size_t 类型为无符号整型(unsigned integer type);count 为元素数组的大小,每个元素占用 size 个字节;stream 为指向文件的 FILE 指针。
#include <stdio.h> #include <stdlib.h> // exit() void copy_with_fgetc(const char src[], const char dst[]) { FILE *fpbr, *fpbw; // Try to open source file fpbr = fopen(src, "rb"); if (fpbr == NULL) { printf("Error for opening source file %s!\n", src); exit(1); } // Try to open destination file fpbw = fopen(dst, "wb"); if (fpbr == NULL) { printf("Error for opening destination file %s!\n", dst); exit(1); } // Copy file with fgetc() and fputc() int val = 0; while ((val = fgetc(fpbr)) != EOF) fputc(val, fpbw); printf("Copy file successfully!\n"); fclose(fpbr); fclose(fpbw); } void copy_with_fread(const char src[], const char dst[]) { FILE *fpbr, *fpbw; // Try to open source file fpbr = fopen(src, "rb"); if (fpbr == NULL) { printf("Error for opening source file %s!\n", src); exit(1); } // Try to open destination file fpbw = fopen(dst, "wb"); if (fpbr == NULL) { printf("Error for opening destination file %s!\n", dst); exit(1); } // Copy file with fread() and fwrite() char ch; while (fread(&ch, sizeof(char), 1, fpbr) != 0) fwrite(&ch, sizeof(char), 1, fpbw); printf("Copy file successfully!\n"); fclose(fpbr); fclose(fpbw); } void copy_with_fread2(const char src[], const char dst[]) { FILE *fpbr, *fpbw; // Try to open source file fpbr = fopen(src, "rb"); if (fpbr == NULL) { printf("Error for opening source file %s!\n", src); exit(1); } // Try to open destination file fpbw = fopen(dst, "wb"); if (fpbr == NULL) { printf("Error for opening destination file %s!\n", dst); exit(1); } // Copy file with buffer fread() and fwrite() size_t len = 0; char buffer[BUFSIZ] = {‘\0‘}; // BUFSIZ macro defined in <stdio.h> while ((len = fread(buffer, sizeof(char), BUFSIZ, fpbr)) > 0) fwrite(buffer, sizeof(char), len, fpbw); printf("Copy file successfully!\n"); fclose(fpbr); fclose(fpbw); } int main() { const char src[] = "HelloWorld.exe"; const char dst1[] = "E:/HelloWorld1.exe"; const char dst2[] = "E:\\HelloWorld2.exe"; const char dst3[] = "E:\\HelloWorld3.exe"; copy_with_fgetc(src, dst1); copy_with_fread(src, dst2); copy_with_fread2(src, dst3); return 0; }
注:在 Windows 系统中,如果使用目录结构,可以用斜杠 ‘/’ 代替反斜杠 ‘\’。如果需要使用反斜杠,则必须增加一个反斜杠进行转义。
标签:lan event and utc size error sign success 文件复制
原文地址:https://www.cnblogs.com/klchang/p/12180817.html