What does c!='n' do in a for statement?

I am a beginner and was learning to code using k&r's c programming book. Now there is this example of "a program to input set of text lines and print the longest"

I am giving you the whole code:

    #include<stdio.h>
    #define MAXLINE 1000

    int getline(char line[], int maxline);
    void copy(char to[], char from[]);

    int main()
    {
    int len;
    int max;
    char line[MAXLINE];
    char longest[MAXLINE];
    max=0;

    while((len=getline(line,MAXLINE))>0)
    if(len>max)
    {
    max=len;
    copy(longest,line);
    }
    if(max>0)
    printf("%s",longest);
    return 0;
    }

    int getline(char s[], int lim)
    {
    int c,i;
    for(i=0;i<lim-1&&(c=getchar())!=EOF&&c!='n';i++)
    s[i]=c;
    if(c=='n')
    {
    s[i]='n';
    i++;
    }
    s[i]='�';
    return i;
    }

    void copy(char to[], char from[])
    {
    int i;
    i=0;
    while((to[i]=from[i])!='�')
    i++;
    }

Now tell me, in getline function, in the statement:

    for(i=0;i<lim-1&&(c=getchar())!=EOF&&c!='n';i++)

why do we use " c!='n' "

and what is the meaning of code after this for statement i.e.

     s[i]=c;
     if(c=='n)
     {
     s[i]=c;
     i++;
     }
     s[i]='�'

why have we used s[i]='�' in this?

and i++; statement in if(c=='n') condition?