C中的文件擴展名爲用戶輸入

Question

我有一個保存功能，我需要我的程序來識別文件擴展名並將其與文件擴展名分開。我已閱讀 Extracting the extension of a file 但我的另存爲功能不是主要的，所以我不能有argv [1]。這裏是我完整的代碼至今：

#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

以下行是正確的：

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

然而strtok回報char*並已宣佈filename和fileext單char。另請注意，應該有與filename緩衝區關聯的內存。將其更改爲：

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

還要考慮檢查這些調用的返回值，因爲可能會發生一些錯誤。

Answer 2

你可以擁有的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; 
}