How change the file path/directory where a file created in c program is saved?-CodePudding

im new to C, im trying to save a file created in the c program beginner.c in a directory called casetudy. How can I implement that as fileopen() funtion only accepts 2 arguments. The FILE_NAME also dynamically changes, how can I do both accept dynamically changing files names and a fixed directory path?

#include<stdio.h>
#include<stdlib.h>
#include<unistd.h>
#define FILE_NAME "tex.txt"

int main(){
FILE* file_ptr = fopen(FILE_NAME, "w");
fclose(file_ptr);
}

CodePudding user response：

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
// #include <unistd.h> you don't need this
#define FILE_NAME "tex.txt"

int main(void) // Use a valid prototype for main
{
    char path[256] = {0}; // Buffer for dynamic path

    puts("Enter a path:");
    // Get the path leaving room for FILE_NAME
    if (fgets(path, sizeof(path) - strlen(FILE_NAME), stdin))
    {
        // Strip the trailing new line
        path[strcspn(path, "\n")] = 0;
    }
    // Concat FILE_NAME
    strcat(path, FILE_NAME);

    FILE *file = fopen(path, "w");

    // Always check the result of fopen
    if (file == NULL)
    {
        perror("fopen");
        exit(EXIT_FAILURE);
    }
    // Do your stuff ...
    fclose(file);
    return 0;
}

what is its the other way round the path is fixed the filename is dynamic?

char path[256] = "/your/fixed/path/";
size_t len = strlen(path);

puts("Enter a file name:");
// Get the file name leaving room for the path
if (fgets(path   len, sizeof(path) - len, stdin))
{
    // Strip the trailing new line
    path[strcspn(path, "\n")] = 0;
}
// Nothing to concat

FILE *file = fopen(path, "w");
...