How can I get a string from input without including a newline using fgets? [duplicate]
Asked Answered
E

2

13

I'm trying to write an inputted string elsewhere and do not know how to do away with the new line that appears as part of this string that I acquire with stdin and fgets.

 char buffer[100];
 memset(buffer, 0, 100);
 fgets(buffer, 100, stdin);
 printf("buffer is: %s\n stop",buffer);

I tried to limit the amount of data that fgets gets as well as limiting how much of the data is written but the new line remains. How can I simply get the inputted string up to the last character written with nothing else?

Evocator answered 15/12, 2014 at 18:49 Comment(3)
scanf("%99[^\n]%*c", buffer);Termitarium
@Termitarium scanf("%99[^\n]%*c", buffer) will not read anything into buffer if the first char is '\n'. The '\n' remains in stdin.Yachtsman
Do you want to read a line and leave the '\n' in the input stream, or do you want to read a line including the '\n' and then discard the '\n'? (This will affect the next input operation, which will or will not see the '\n' waiting for it.)Commitment
A
5

try

fgets(buffer, 100, stdin);
size_t ln = strlen(buffer)-1;
if (buffer[ln] == '\n')
    buffer[ln] = '\0';
Amalgam answered 15/12, 2014 at 18:59 Comment(0)
Y
5

Simply look for the potential '\n'.

After calling fgets(), If '\n' exists, it will be the last char in the string (just before the '\0').

size_t len = strlen(buffer);
if (len > 0 && buffer[len-1] == '\n') {
  buffer[--len] = '\0';
}

Sample usage

char buffer[100];
// memset(buffer, 0, 100); not needed
if (fgets(buffer, sizeof buffer, stdin) == NULL) { // good to test fgets() result
  Handle_EOForIOerror();
}
size_t len = strlen(buffer);
if (len > 0 && buffer[len-1] == '\n') {
  buffer[--len] = '\0';
}
printf("buffer is: %s\n stop",buffer);

Notes:

buffer[strlen(buffer)-1] is dangerous in rare occasions when the first char in buffer is a '\0' (embedded null character).

scanf("%99[^\n]%*c", buffer); is a problem if the first char is '\n', nothing is read and '\n' remains in stdin.

strlen() is fast as compared to other methods: https://codereview.stackexchange.com/a/67756/29485

Or roll your own code like gets_sz

Yachtsman answered 15/12, 2014 at 19:50 Comment(0)

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