Dfyjkt

I am trying to practice an example on stack, and I am finding a bit difficulty in printing the answer of this example.

/* A letter means push and an asterisk means pop in the
 following sequence. Give the sequence of values returned by the pop operations
 when this sequence of operations is performed on an initially empty LIFO stack.

 E A S * Y * Q U E * * * S T * * * I O * N * * *
*/
#include<stdio.h>

char a[40] = "EAS*Y*QUE***ST***IO*N***", s[20], b[30];
int top = -1;

This one is the PUSH operation.

void push(char a)

 int i=0;
 if (top >= 24)
 printf("Overflow.");
 else if (a == '*')
 b[i++] = pop();
 else
 s[++top]= a;

And this is the POP operation.

 void pop()
 
 if (top < 0)
 printf("Underflow");
 else
 top--;

 return s[top+1];
 

And the main function.

void main()

 int i;
 printf("%sn", a);

 for (i=0; i<24; i++)
 push(a[i]);

 for (i=0; i<24; i++)
 printf("%c", b[i]);

In your push function, you are declaring int i as a local variable. With this in mind, can you see how your line b[i++]=pop(); will always evaluate to b[0]=pop();?

Edit:
Here are the suggested changes. Per Tim's suggestion, you should make int i a static variable.

void push(char a)

static int i=0;
 if(top>=24)
 printf("Overflow.");
 else if(a=='*')
 b[i++]=pop();
 else
 s[++top]=a;

You also need to make pop return a char instead of void

char pop()
 
 if(top<0)
 printf("Underflow");
 else
 top--;

 return s[top+1];
 

jdoodle