How to allocate dynamic memory for a text file in C?

Question

C++ / C#

I have a function:

FILE* openInputFile()
{
    printf("Enter the name of the input file: ");
    char* inputFileName;
    scanf("%s", &inputFileName);
    printf("%s", inputFileName);
    if (strstr(inputFileName, ".txt") == NULL)
        inputFileName = strcat(inputFileName, ".txt");
    printf("%s", inputFileName);
    FILE* inputFile = fopen(inputFileName, "r");
    return inputFile;
}

When you run it, the program crashes with the SIGSEGV error. Maybe you need to allocate dynamic memory for this file?
(Now I checked, it does not depend on the file size. What could be the error then?)

Answer 1

char* inputFileName;

It would be weird if it didn't crash, since inputFileName now points somewhere in space.
Dummies usually do this: and then they think - how is it that they broke me? who are smarter do this:
char inputFileName[256];

char *inputFileName;
inputFileName = (char *) calloc(256, 1);

(this, of course, is also not a star - you need to take into account the maximum allowable length of the path and file name, but it's much better)