PRACTICE PROBLEM 2 -(24-1 to 31-1) : SINGULAR TO PLURAL

#include<stdio.h>
#include<string.h>
int main()
{

char s[100];
char p[100];
scanf("%s",s);
int l=strlen(s);
char last=s[l-1];
char last_two[2];
last_two[0]=s[l-2];
last_two[1]=s[l-1];
int i;
for(i = 0; s[i]; i++){
    s[i] = tolower(s[i]);
    }
strcpy(p,s);
if(strcmp(last_two,"ch")==0 || strcmp(last_two,"sh")==0 || last=='s')
{
p[l]='e';
p[l+1]='s';
p[l+2]='\0';
    }
   
else if(last=='y')
{
p[l-1]='i';
p[l]='e';
p[l+1]='s';
p[l+2]='\0';
    }
    else
    {
    p[l]='s';
}
printf("%s %s",s,p);
return 0;
}