Infix to Postfix Expression

#include<stdio.h>

#include<string.h>

#include<ctype.h>

main()

{

char
ans;

do

{

char
infix[50],stack[50],x;

int
top=0,i=0;

clrscr();

printf("\n\n\t\t\tCONVERSION
OF INFIX TO POSTFIX EXPRESSION");

printf("\n\t\t\t*****************************************");

printf("\n\nENTER
THE INFIX EXPRESSION :->");

fflush(stdin);

gets(infix);

printf("\n\nTHE
REQUIRE POSTFIX FORM IS:->");

stack[0]='#';

x=infix[0];

while(x!='\0')

{

if(isalnum(x))

printf("%c",x);

else if(x==')')

{

while(stack[top]!='(')

printf("%d",stack[top--]);

top--;

}

else

{

while(isp(stack[top])>=icp(x))

printf("%c",stack[top--]);

stack[++top]=x;

}

x=infix[++i];

}

while(top>0)

printf("%c",stack[top--]);

printf("\n\nDO
U CONTINUE (Y/N):->");

scanf("%s",&ans);

}while(ans=='y'||ans=='y');

getch();

}

int
isp(char c)

{

if(c=='*'||c=='/')
return 2;

if(c=='+'||c=='-')
return 1;

if(c=='(') return 0;

if(c=='#') return -4;

}

int
icp(char c)

{

if(c=='*'||c=='/')
return 2;

if(c=='+'||c=='-')
return 1;

if(c=='(') return -4;

}