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cnewlinefgetsstrcat

How to add a character "\t" into a string before the newline character "\n"

I am wondering how to take a line of string and add a tab character before the new line character. Right now I'm using fgets to get the line then using 

strcat(line_data, "\t");

but that just adds the tab after the newline character

Solution

  • Assuming that line_data has enough memory:

    char* newline = strchr(line_data, '\n');
newline[0] = '\t';
newline[1] = '\n';
newline[2] = '\0';

    Of course, if it doesn't, you have to do something like this:

    size_t len = strlen(line_data);
char* newstr = malloc(len + 2); /* one for '\t', another for '\0' */
memcpy(newstr, line_data, len);
newstr[len - 1] = '\t'; /* assuming '\n' is at the very end of the string */
newstr[len] = '\n';
newstr[len + 1] = '\0';