Thread: Help Please - program to display file renders Windows Program Error

Code:

int main()
{
    char filename[20];
    // Allocate a string to store filename - does PC interpret whitespace at end of filename?
    printf("Please enter the filename");
    scanf("%s", &filename);
    // Request name of file to open, store in filename
    FILE *fp;
    fp = fopen(filename,"r");
    // Create file pointer, open file stored in string filename
    char filetext[1024];
    // Create string 1024 cells long to hold text from file
    int i = 0;
    // Compiler doesn't like my fore loops, explicitly create i
    for(i = 0; i <= 1023; i++) {
          filetext[i] = fgetc(filename);
          // Place each character of the file into a different string cell, one after the other
          tolower(filetext[i]);
          // Move through string, converting text to lowercase
          }
    printf("%s",filetext);
    // Display the contents of the file on screen, but...
    if(i == ' ') {
    // If the string cell is blank, i.e a space
         printf("\n");
         // move onto a new line
         }
     }

Now, let's see what you are doing here:

Code:

    scanf("%s", &filename);

You are passing scanf the address to the pointer of the filename buffer.

Code:

fp = fopen(filename,"r");

Doh!

Code:

    for(i = 0; i <= 1023; i++) {

filetext[1023] is the last byte of the filetext buffer, so if you don't set the last byte to 0, then you will see a buffer overrun(overread?).

Code:

          tolower(filetext[i]);

tolower() returns lowercase filetext[i], but... the return value is not used.

Code:

    if(i == ' ') {

If i is 32, it enters that if. (It is always 1024 after the loop)

Your indentation is buggy (last 2 lines).