Cutting ' \0' from strings [closed]

问题

I have a 2D array of strings loaded with getline from stdin example :

Hi my name is John.
I like chocolate.

Then i want to search if entered string / substring matches with one of the string arrays example :

Ohn. - matches at line 1
chocolate. - matches at line 2

I'm using standart function strstr :

if ( ( strstr(array[i],string) ) != NULL ) {
      printf("Match");
}

The problem is that when i want to find a string which is not at the end of the string like i wrote , it does not match because probably when i want to find "like" in the string it probably compares like\0 with "like" so it will never match.

When i load the line with getline to buffer i used function: strlen(buffer)-1 then i allocated memory for strlen(buffer) - 1 * sizeof(char) and then copied it to the array with memcpy function. Everything worked perfectly but when the string has lenght of 7-8 it puts 2 undefined characters at the end of the string example :

Enter string :testtttt
memcpy to allocated array of strlen(string) - 1
printed string from array looks like : testttttt1� or testtttttqx etc..

Strings with length less then 7 or more than 8 characters work perfectly. If you know how to fix this problem or know a better way to make from string\0 just string without \0 let me know i will be thankful.

Part of the code which does not work. Only matches wtith ending strings like i mentioned.Pole is 2D array of strings, line is buffer where the string is stored.

size_t len = 0;
char *line = NULL;
int number;
while ( (number = getline(&line, &len, stdin ) ) != -1 ) {
    for (i = 0; i < index; i++) {
            if(strstr(pole[i], line) != NULL) {
               printf("Match");
            }
    }
}


    6 
John.

'Hi my name is John.
' contain 'John.
'
'Testing stuff
' does not contain 'John.
'
'I do not know what to write
' does not contain 'John.
'
8 
Testing

'Hi my name is John.
' does not contain 'Testing
'
'Testing stuff
' does not contain 'Testing
'
'I do not know what to write
' does not contain 'Testing
'
5 
know

'Hi my name is John.
' does not contain 'know
'
'Testing stuff
' does not contain 'know
'
'I do not know what to write
' does not contain 'know
'

回答1:

Your problem is evident in your debug output. getline does not strip the newline from the input, so for example you are searching for:

"know\n"

"I do not know what to write\n"

So your problem is not about stripping the \0 string terminator, but rather stripping the \n line-end.

That can be achieved in a number of ways, for example:

char* newline = strrchr( line, '\n' ) ;
if( newlineaddr != NULL )
{
    *newlineaddr  = '\0' ;
}

size_t newlineindex = strcspn(line, "\n") ;
line[newlineindex] = '\0' ;

The first copes with multi-line input (not needed in this case) - only removing the last newline, while the second is more succinct.

回答2:

Searching through a function in c is very easy.You can use strcmp for comparison and strcmp comes with different flavours of it like stricmp,strncmp and so on...Here is the link

来源：https://stackoverflow.com/questions/34151059/cutting-0-from-strings

标签

string

strstr