Thread: Debug Assertion Failed error

Hi, I've been having problems with this code, a few people have looked at it and say it should work but I get a 'Debug Assertion Failed' error. It says 'expression str!=NULL'.

Not sure what the problem is, here is the segment that seems to contain the error.

Code:

	FILE *fp;	
	fp=fopen("texts.txt","r");

	if (fp == NULL) 		
		printf("Can't open file!\n");	
	else		
		printf("File opened!\n");          
	

	fgets (message , 400 , fp);	
	
	fclose(fp); //all file use is complete

Here is the complete code, the message variable has been declared and holds 400 chars so it should be fine.

Code:

#include<stdio.h>
#include<string.h> 
#include<ctype.h>

void main()
{	
	
	/*declare and initialise variable*/	
	char message[400];	
	int i=0;	
	char filename[30]; 
	char *lower;
	
	/*prog info*/	
	printf("This program will read in a file of your choice and print it out to the screen.\nCreated 30/11/10 v.10\n\n\n\n");  	
	
	/*Input of file name from keyboard*/
	printf("Please input the name of the file you wish to use inc .txt suffix\nTip: File should be stored in the same directory as the program file\n");
	scanf("%s",filename);
	
	FILE *fp;	
	fp=fopen("upper.txt","r");

	if (fp == NULL) 		
		printf("Can't open file!\n");	
	else		
		printf("File opened!\n");          
	

	fgets (message , 400 , fp);	
	
	fclose(fp); //all file use is complete 

	/*Converts each char in the array to lower case*/
	for (lower=message;*lower!='\0';++lower)
   {
       *lower=tolower(*lower);
   }

	/*Prints text*/
	printf("\nYour text for encryption:\n");    
	puts (message);

}

Originally Posted by ssharish2005

The code seems to working fine for me. Where excatly does your code crashed, are you able to read the file name. Though your not using filename user entered.

ssharish

Hi,

I'm able to read in fine, it crashes after the user input the filename (I know I'm not using it yet, I have no idea how to do it! Still trying to figure it out).

If you can't open the file you should not continue on in your program as if it were opened successfully, which you are currently doing.