C中的文件扩展名为用户输入

Question

我有一个保存功能，我需要我的程序来识别文件扩展名并将其与文件扩展名分开。我已阅读 Extracting the extension of a file 但我的另存为功能不是主要的，所以我不能有argv [1]。这里是我完整的代码至今：

#include <stdio.h> 
#include <errno.h> 

void save_as() 
{ 
    // user enters their desired name for the file 
    char filename; 
    char fileext; 
    printf("Filename:\t"); 
    scanf("%s", &filename); 
    filename = strtok(filename, "."); // according to the link I mentioned above this should have been: filename = strtok(argv[1], "."); 
    fileext = strtok(NULL, "."); 
} 

int main() 
{ 
    save_as(); 
    return 0; 
} 

Answer 1

以下行是正确的：

char filename; 
char fileext; 
printf("Filename:\t"); 
scanf("%s", &filename); 
filename = strtok(filename, "."); 
fileext = strtok(NULL, "."); 

然而strtok回报char*并已宣布filename和fileext单char。另请注意，应该有与filename缓冲区关联的内存。将其更改为：

char filename[255]; 
printf("Filename:\t"); 
scanf("%254s", &filename); 
filename = strtok(filename, "."); 
char* fileext = strtok(NULL, "."); 

还要考虑检查这些调用的返回值，因为可能会发生一些错误。

Answer 2

你可以拥有的argv [1]：

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

void save_as(char *filename) 
{ 
    // user enters their desired name for the file 
    char *fileext; 

    filename = strtok(filename, "."); // according to the question I mentioned above this should have been: filename = strtok(argv[1], "."); 
    fileext = strtok(NULL, "."); 
} 

int main(int argc, char **argv) 
{ 
    if(argc != 2) 
    { 
     printf("usage: myprogram myfile.myextension"); 
     return 0; 
    } 
    save_as(argv[1]); 

    return 0; 
}