fgets and readRestOfLine errors - c

Question

I got errors while creating a menu using fgets and readrestofline function. I don't know where is the error coming from. Am I missing something? After compiling, errors shows at "fgets", "readrestofline" and "stdin".
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
int printMenu(void)
{
int option;
char input[3];
while((option != 3)||(option < 4)||(option > 0))
{
printf("Welcome\n");
printf("---------------------\n");
printf("1.Play \n2.Display Scores\n3.Quit\n");
printf("Please enter your choice: ");
fgets(input, 3, stdin);
if (input[strlen(input) - 1] != '\n')
{
printf("Input was too long.\n");
readRestOfLine();
}
else
{
input[strlen(input) - 1] = '\0';
}
switch (option)
{
case 1:
printf("Loading ...\n");
break;
case 2:
printf("Loading ...\n");
break;
case 3:
printf("Quitting...\n");
exit(0);
break;
default:
printf("Invalid ! Please choose again.\n");
break;
}
}
}
void readRestOfLine()
{
int c;
/*read until the end of the line or end-of-file*/
while ((c = fgets(stdin)) != '\n' && c != EOF);
/*clear the error and end-of-file flags*/
clearerr(stdin);
}

Answer 1

errors while creating a menu using fgets...
Regarding your code line:
while ((c = fgets(stdin)) != '\n' && c != EOF);
fgets, prototype is:
char *fgets (char Line_Buffer[], int Number_of_Chars, FILE *Stream);
Reads characters from the specified input stream into a lineBuffer until end-of-file is encountered, a newline character is read, or (number_ofChars - 1) characters are read. The newline character is retained. An ASCII NUL byte is appended to the end of the string. If successful, the function returns a pointer to lineBuffer.
you have only provided 1 of the 3 necessary arguments.
Example usage:
char buf[80];//line buffer with space for 80 char
int c;
while(fgets(buf, 80, stdin))
{
//do something with buf
}
Also, instead of using the line(s): (undefined behavior)
if (input[strlen(input) - 1] != '\n') //used twice in your code example
Consider testing the contents of the string(s) like this:
if(strstr(input, "\n"))//change the second argument to search for other values
{
//do something
}
Note that your first usage of fgets in the posted code is syntactically correct.