完整题目：
编程模拟DOS或linux下的复制文件命令copy，将一个文本文件（源文件）复制到另一个文本文件（目标文件）中。命令行格式为：
命令名 源文件名 目标文件名
假设本题程序编译连接后的可执行文件名为fcopy，则下面命令将scr.txt复制到scr.bak中
fcopy src.txt scr.bak
解法：
1.利用fgetc和fputc函数
#include<stdio.h>
int fcopy(char *,char *);
int main(int argc,char *argv[])
{
int i;
if (argc < 3) {
printf("The command syntax is incorrect.fcopy [source filename] [target filename]\n");
exit(0);
}
if (fcopy(argv[1], argv[2]) == 0)
printf("No such a file:%s or %s\n",argv[1],argv[2]);
return 0;
}
int fcopy(char*sourcename, char*targetname)
{
char c;
FILE* fp1, * fp2;
if (!(fp1 = fopen(sourcename, "r")))return 0;
if (!(fp2 = fopen(targetname, "w")))return 0;
while ((c = fgetc(fp1)) != EOF)fputc(c,fp2);
fclose(fp1);
fclose(fp2);
return 1;
}
2.文件重定向
#include<stdio.h>
int fcopy(char *,char *);
int main(int argc,char *argv[])
{
int i;
if (argc < 3) {
printf("The command syntax is incorrect.fcopy [source filename] [target filename]\n");
exit(0);
}
if (fcopy(argv[1], argv[2]) == 0)
printf("No such a file:%s or %s\n",argv[1],argv[2]);
return 0;
}
int fcopy(char*sourcename, char*targetname)
{
char c;
if (freopen(sourcename, "r", stdin) == NULL)return 0;
if (freopen(targetname, "w", stdout) == NULL)return 0;
while ((c = getchar()) != EOF)putchar(c);
return 1;
}
3.fgets函数和fputs函数
#include<stdio.h>
int fcopy(char*, char*);
int main(int argc, char* argv[])
{
int i;
if (argc < 3) {
printf("The command syntax is incorrect.fcopy [source filename] [target filename]\n");
exit(0);
}
if (fcopy(argv[1], argv[2]) == 0)
printf("No such a file:%s or %s\n", argv[1], argv[2]);
return 0;
}
int fcopy(char* sourcename, char* targetname)
{
char a[81];
FILE* fp1, * fp2;
if (!(fp1 = fopen(sourcename, "r")))return 0;
if (!(fp2 = fopen(targetname, "w")))return 0;
while (fgets(a,80,fp1)!=NULL)fputs(a,fp2);
fclose(fp1);
fclose(fp2);
return 1;
}
4.fscanf函数和fprintf函数
#include<stdio.h>
int fcopy(char*, char*);
int main(int argc, char* argv[])
{
int i;
if (argc < 3) {
printf("The command syntax is incorrect.fcopy [source filename] [target filename]\n");
exit(0);
}
if (fcopy(argv[1], argv[2]) == 0)
printf("No such a file:%s or %s\n", argv[1], argv[2]);
return 0;
}
int fcopy(char* sourcename, char* targetname)
{
char c;
FILE* fp1, * fp2;
if (!(fp1 = fopen(sourcename, "r")))return 0;
if (!(fp2 = fopen(targetname, "w")))return 0;
while (fscanf(fp1,"%c",&c)!=EOF)fprintf(fp2,"%c",c);
fclose(fp1);
fclose(fp2);
return 1;
}