Hello!

I have a little problem with my code, I have been programming C for a couple of months now, and I need some help on this one I want to read a string from a file called Test.txt. Inside the file there is a string "Hello World!". And if that string is alredy there, the program should return 0 from the function read_file to read2, but it always returns 1, and in that way, it always writes "Hello World!" again to the file, which is not what I want..

#include <stdio.h>
FILE *file;

int read_file(char read [30]) {

file = fopen ("Test.txt", "rt");
fscanf(file, "%s" , read);
if (read == "Hello World!")
return 0;
else
return 1;
fclose(file);
}

int main (void) {
char read1 [30];
int read2;
read2=read_file(read1);
file = fopen ("Test.txt", "wt");
printf("%d \n", read2);
if (file == NULL)
printf("Can't open file. \n");
else if (read2 == 0)
printf ("That was alredy inside the file, closing...\n") && fclose(file);
else if (read2 == 1)
fprintf(file, "Hello World!") && printf ("Successfully written to the file. \n") && fclose(file);
getchar();
}

Code:

read == "Hello World"

This is not the correct way to compare strings. Use strcmp.

Thank you so much for taking your time, but I don't understand how I would use it. I would be very glad if you could show me an example of how I would go with it

The link I provided has examples on the page. But here is how you would check to see if two strings are equal. strcmp is case-sensitive; it continues until a null character is reached in one of the strings.

Code:

if (strcmp(read, "Hello, World!") == 0) // Checks to see if the strings are equal
  return 0;
return 1;

Also, your fclose should come before your return statement, otherwise it will never be executed. And in your main function, return 0 at the end to signal a successful exit. This value is sometimes used by the operating system.

Okay, thank you very much :D