1、

[root@centos79 test]# cat test.c
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

int main(int argc, char * argv[])
{
        char ch;
        FILE * in, * out;
        char name[30];

        if(argc < 2)
        {
                printf("usage: %s filename\n", argv[0]);
                exit(EXIT_FAILURE);
        }

        if((in = fopen(argv[1], "r")) == NULL)
        {
                printf("fail to open the %s\n", argv[1]);
                exit(EXIT_FAILURE);
        }

        strcpy(name, argv[1]);
        strcat(name, ".copy");

        if((out = fopen(name, "w")) == NULL)
        {
                printf("fail to open the %s\n", name);
                exit(EXIT_FAILURE);
        }

        while((ch = getc(in)) != EOF)
        {
                putc(ch, out);
        }


        if(fclose(in) != 0 || fclose(out) != 0)
        {
                printf("fail to close the files!\n");
                exit(EXIT_FAILURE);
        }

        return 0;
}

 

[root@centos79 test]# ls
plink.map  test.c
[root@centos79 test]# gcc test.c
[root@centos79 test]# ls
a.out  plink.map  test.c
[root@centos79 test]# ./a.out
usage: ./a.out filename
[root@centos79 test]# ./a.out plink.map
[root@centos79 test]# ls
a.out  plink.map  plink.map.copy  test.c
[root@centos79 test]# md5sum *
3f46af47fb12b6a73fb4134f083529bf  a.out
3ac45c2965cc65f5973df626dfdd016c  plink.map
3ac45c2965cc65f5973df626dfdd016c  plink.map.copy
d346acecc65fb125312424cdaf9f2ef3  test.c

 

2、

[root@centos79 test]# cat test.c
#include <stdio.h>
#include <stdlib.h>

int main(int argc, char * argv[])
{
        char ch;
        FILE * in, * out;
        char name[50];

        if(argc < 2)
        {
                printf("usage: %s filename\n", argv[0]);
                exit(EXIT_FAILURE);
        }

        if((in = fopen(argv[1], "r")) == NULL)
        {
                printf("fail to open %s!\n", argv[1]);
                exit(EXIT_FAILURE);
        }

        printf("please input the out name:");
        scanf("%s", name);

        if((out = fopen(name, "w")) == NULL)
        {
                printf("fail to open %s!\n", name);
                exit(EXIT_FAILURE);
        }

        while((ch = getc(in)) != EOF)
        {
                putc(ch, out);
        }

        if(fclose(in) != 0 || fclose(out) != 0)
        {
                printf("fail to close the files!\n");
                exit(EXIT_FAILURE);
        }

        return 0;
}

 

[root@centos79 test]# ls
plink.map  test.c
[root@centos79 test]# gcc test.c
[root@centos79 test]# ls
a.out  plink.map  test.c
[root@centos79 test]# ./a.out
usage: ./a.out filename
[root@centos79 test]# ./a.out plink.map
please input the out name:plink.map.bak
[root@centos79 test]# ls
a.out  plink.map  plink.map.bak  test.c
[root@centos79 test]# md5sum *
c2f089ea14f8579de89af7c9a76c87e4  a.out
3ac45c2965cc65f5973df626dfdd016c  plink.map
3ac45c2965cc65f5973df626dfdd016c  plink.map.bak
d598967c6b77d67aae7a362f6b8e8b01  test.c