C language, to achieve three chess games

#include<stdio.h>

#include<stdlib.h>

#include <time.h>

#define a 3

#define b 3

void qi(char san[a][b])

{

for(int i=0;i<a;i++)

{

 for(int j=0;j<b;j++)

 {

  san[i][j]=' ';

 }

}

}

void bu(char san[a][b])

{

printf("+---+---+---+\n");

for(int i=0;i<a;i++)

{

 printf("| %c | %c | %c |\n",san[i][0],san[i][1],san[i][2]);

 printf("+---+---+---+\n");

}

}

void play(char san[a][b])

{

while(1)

{

 int x,y;

 printf(" Please enter the coordinates you want （ Space separates the middle ）\n");

 scanf("%d%d",&x,&y);

 if(x<0||x>=a||y>=b||y<0)

 {

  printf(" Input error , Please be there. （1,1） To （3,3） Re input within the range of \n");

  continue;

 }

 else if(san[x][y]!=' ')

  {

   printf(" This seat already has chess pieces \n");

   continue;

  }

 else

 {

  san[x][y]='x';

  break;

       }  

   }

}

void dian(char san[a][b])

{

while(1)

{

 int x=rand()%a;

 int y=rand()%b;

 if(san[x][y]!=' '||san[x][y]=='x')

 {

  continue;

 }

 else

 {

  san[x][y]='o';

  break;

 }

}

}

int ping(char san[a][b])

{

for(int i=0;i<a;i++)

{

 for(int j=0;j<b;j++)

 {

  if(san[i][j]==' ')

  {

   return 0;

  }

 }

}

return 1;

}

char pan(char san[a][b])

{

for(int i=0;i<a;i++)

{

 if(san[i][0]!=' '&&san[i][0]==san[i][1]&&san[i][1]==san[i][2])

 {

  return san[i][0];

 }  

}

for(int j=0;j<b;j++)

{

    if(san[0][j]!=' '&&san[0][j]==san[1][j]&&san[1][j]==san[2][j])

 {

   return san[1][j];  

 }

}

if(san[0][0]==san[1][1]&&san[1][1]==san[2][2]&&san[0][0]!=0)

{

 return san[0][0];

}

if(san[2][0]==san[1][1]&&san[1][1]==san[0][2]&&san[2][0])

{

 return san[2][0];

}

if(ping(san)==1)

{

 return 'h';

}

return 'j';

}

void game()

{

char ret='0';

char san[a][b]={0};// Define a 3*3 Array of

qi(san);// Yes 3*3 Array to initialize

bu(san);// Layout chessboard structure

while(1)

{

 play(san);// Players play chess

 bu(san);// Layout chessboard structure

 ret=pan(san);

 if(ret!='j')

 {

  break;

 }

 dian(san);// The computer plays chess

 bu(san);// Layout chessboard structure

 ret=pan(san);

 if(ret!='j')

 {

  break;

 }

}

   if(ret=='x')

{

 printf(" Congratulations on your victory \n");

}

else if(ret=='o')

{

 printf(" The computer won \n");

}

else

{

 printf(" It ends in a draw \n");

}

}

int menu()

{

int en;

printf("##########################\n");

printf("##1. Enter the game  0. Quit the game ##\n");

printf("##########################\n");

scanf("%d",&en);

return en;

}

int main()

{

srand((unsigned int)time(0));

while(1)

{

 system("cls");

 int en=menu();

 if(en==1)

 {

  game();

 }

 else if(en==0)

 {

  printf(" Quit the game \n");

  break;

 }

 else

 {

  printf(" Input error ！ Please re-enter ！\n");

  continue;

 }

}

system("pause");

return 0;

}