codechef KNIGHTMV - "correctness of knight move" solution

codechef KNIGHTMV - "correctness of knight move": http://www.codechef.com/problems/KNIGHTMV
codechef KNIGHTMV - "correctness of knight move" editorial :  http://discuss.codechef.com/questions/4132/knightmv-editorial

codechef KNIGHTMV - "correctness of knight move" solution :  http://ideone.com/hPy4KW

#include <iostream>

#include <stdio.h>

#include <string.h>

using namespace std;

int main() {

int t, flag;

char s[15];

scanf("%d", &t);

getchar();

while(t--) {

flag=0;

gets(s);

if(s[0]<'a' || s[0]>'h' || s[1]<'1' || s[1]>'8' || s[2]!='-' || s[3]<'a' || s[3]>'h' || s[4]<'1' || s[4]>'8' || strlen(s)!=5) {

cout<<"Error"<<endl;

}

else {

if(s[0]>s[3]) {

if(s[1]>s[4]) {

if(s[0]-s[3]==1 && s[1]-s[4]==2) flag=1;

else if(s[0]-s[3]==2 && s[1]-s[4]==1) flag=1;

}

else {

if(s[0]-s[3]==1 && s[4]-s[1]==2) flag=1;

else if(s[0]-s[3]==2 && s[4]-s[1]==1) flag=1;

}

}

else {

if(s[1]>s[4]) {

if(s[3]-s[0]==1 && s[1]-s[4]==2) flag=1;

else if(s[3]-s[0]==2 && s[1]-s[4]==1) flag=1;

}

else {

if(s[3]-s[0]==1 && s[4]-s[1]==2) flag=1;

else if(s[3]-s[0]==2 && s[4]-s[1]==1) flag=1;

}

}

if(flag==1) cout<<"Yes"<<endl;

else cout<<"No"<<endl;

}

}

return 0;

}

note: pay attn to difference between <cstdio> and <stdio.h>, i damn used and tried many times gets(), etc with <cstdio>, verdict was always WA, but i changed it to <stdio.h>, AC :)

also, imho many use of && in if condition brings prob may be, i dont know :( my code did not work on that