hey , how do i append a string to input i have received from stdin.
i wanna do somethin likeCode:printf("Please enter a word to search for:\n"); fgets (input,MAX,stdin); check = strtok(input, "\n");
it compiles fine but doesnt seem to append the two strings ?Code:input = strcat(input , " - ");
strcat appends a string to the argument you pass as destination.
In your code, it would append " - " to input.
But beware that strtok actually damages the original input string (it changes the input string you provide it), which might not be what you want...
Originally Posted by Adak
yes, thats what i want it to do , but its not .. i wanted input to be appended with " - " , but its not doing that .. do you mean its because of strtok ?..but thats being called after i append the string. is there any other way to append a string to the input ?
Then you must be doing something "bad" in your code. Will you not show us what you are doing?
sure... here it is..basically im trying to create an amateur dictionary and the words is the file are seperated from the meanings by a " - " , and in case a word is repeated , the function returns the first value it found for example if i search for car it will return alacarte which comes before car in the text file. unless i explicitly search for "car -"
Code:FILE *dict; char buffer[MAX]; char input[MAX]; char *check; char *found; /*...*/ printf("Please enter a word to search for:\n"); fgets (input,MAX-1,stdin); input[strlen(input)+1] = strcat(input , " -"); check = strtok(input, "\n"); fgets (buffer, MAX-1, dict); while (!strstr(buffer, check)) { fgets (buffer, MAX-1, dict); count++; found = strstr(buffer,check); } if(found) printf( "\n%s\n", found );
I'd be very surprised if the first line of this section doesn't give you a warning (should the case be that you don't then you should turn up the warning level of the compiler), as you are assigning the result of strcat to a character in your string (which so happens to be the last character of the length of the string - whether that is BEFORE or after input has been appended is an interesting question, which I beleive the standard doesn't define (so you may have strlen() from before strcat, or from after strcat) - be that as it may, since you don't actually want to do this anyways. Just strcat(input, " -"); will be fine.Code:input[strlen(input)+1] = strcat(input , " -"); check = strtok(input, "\n");
The second line cuts the line off at the newline. Since the input from fgets() has a newline at the end, you'd get something like "abc\n", then append " -" -> a string holding "abc\n -", and then cut it at the strtok(), so you end up with "abc". I don't think that's what you wanted to do.
Also:
If you are planning to append two characters to teh string, maybe you'd like to make that MAX-2, so that you are guaranteed to fit at least 2 more characters in the string.Code:fgets (input,MAX-1,stdin);
--
Mats
Compilers can produce warnings - make the compiler programmers happy: Use them!
Please don't PM me for help - and no, I don't do help over instant messengers.
Not to mention that strlen(input) + 1 is beyond the length of the string itself, and thus a dangerous thing, and also quite unnecessary.
And mats also warns that the line may be undefined behavior since the standard may not guarantee which is done first, the strlen call or the strcat call, so you may get different results depending on which is done first, which may differ in different compilers.
Thank you matsp and Elysia! , i know the strlen function i used was wrong but before that i tried using simply , strcat(input , " -") and even tried assigning it to another char* but i cant seem to append anythin to input after i get the user input. is there a way to append " -" at the same time the user types his input into stdin, so that the value of input is "... -" , so that it doesnt get cut off by strtok() ?
Code:char buffer[MAX]; fgets(input, MAX - 2, stdin); strtok(input, "\n"); strcat(input, " -");
Wow! it worked !that was easy..i feel stupid.. Thank You!
