算法竞赛入门经典 刽子手游戏 Rail ,Hangman judge UVa 489

Hangman Judge
you are to write a program that judges a series of Hangman games. For each game, the answer to the puzzle is given as well as the guesses. Rules are the same as the classic game of hangman, and are given as follows:
The contestant tries to solve to puzzle by guessing one letter at a time.
Every time a guess is correct, all the characters in the word that match the guess will be turned over.'' For example, if your guess iso” and the word is book'', then botho”s in the solution will be counted as solved.''
Every time a wrong guess is made, a stroke will be added to the drawing of a hangman, which needs 7 strokes to complete. Each unique wrong guess only counts against the contestant once.
If the drawing of the hangman is completed before the contestant has successfully guessed all the characters of the word, the contestant loses.
If the contestant has guessed all the characters of the word before the drawing is complete, the contestant wins the game.
If the contestant does not guess enough letters to either win or lose, the contestant chickens out.
Your task as theHangman Judge” is to determine, for each game, whether the contestant wins, loses, or fails to finish a game.
Input
Your program will be given a series of inputs regarding the status of a game. All input will be in lower case. The first line of each section will contain a number to indicate which round of the game is being played; the next line will be the solution to the puzzle; the last line is a sequence of the guesses made by the contestant. A round number of -1 would indicate the end of all games (and input).
Output
The output of your program is to indicate which round of the game the contestant is currently playing as well as the result of the game. There are three possible results:
You win.
You lose.
You chickened out.
Sample Input
1
cheese
chese
2
cheese
abcdefg
3
cheese
abcdefgij
-1
Sample Output
Round 1
You win.
Round 2
You chickened out.
Round 3
You lose.

/*
算法竞赛入门经典 
刽子手游戏 Rail ,Hangman judge UVa 489 
*/
#include "stdio.h" 
#include "string.h"
int left,chance;
    int win, lose;
char a[10],b[10];
int guess(char ch)
{
    int bad = 1;
    for (int i = 0;i <strlen (a) ; i++)
    if(a[i]==ch) 
    {
         left--;a[i] = ' ';bad = 0;
    }
    if(bad) --chance;
    if(!chance) lose = 1;
    if(!left) win = 1;
 } 
int main()
{
    int n,i,j;

    while(scanf("%d%s%s",&n,a,b)==3&&n!=-1)
    {
        printf("round %d\n",n);
        win  = lose = 0;
        left = strlen(a);
        chance = 7;
        for(i=0;i<strlen(b);i++)
        {
            guess(b[i]);
            if(win||lose) break;
        }
        if(win) printf("you win\n");
        else if(lose) printf("you lose\n");
        else printf("you chicked out.\n");
    }
    return 0;
}