Ds_lab/infixPostfix.c at main · farhank9821/Ds_lab · GitHub

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#include <stdio.h>
#include<ctype.h>
char stack[100];
int top=-1;
void push(char x)
{
    stack[++top]=x;
}
char pop()
{
    if(top==-1){
        return -1;}
    else{
        return(stack[top--]);
    }
}
int priority(char x)
{
    if(x=='(')
    return 0;
    if((x=='+') || (x=='-'))
    return 1;
    if((x=='*') || (x=='/'))
    return 2;
    if((x=='^') || (x=='%'))
    return 3;
}
int main()
{
char exp[100];
char *e,x;
printf("enter the expression :");
scanf("%s",exp);
e=exp;
while(*e!='\0')
{
if(isalnum(*e))
printf("%c",*e);
else if(*e=='(')
    push(*e);
else if(*e==')')
{
    while((x=pop())!='(')
    printf("%c",x);
}
else
{
 while(priority(stack[top])>=priority(*e))
 printf("%c",pop());
 push(*e);
}
e++;
}
while(top!=-1)
printf("%c",pop());
return 0;
}