C program to evaluate Prefix Expression using Stack data structure

Simple C program to evaluate Prefix Expression using Stack data structure

Code:

#include<stdio.h>

#include<conio.h>

#include<string.h>

int steck[10];

int top=-1;

void push(int value)

{

steck[top++]=value;

}

int pop()

{

return(steck[top--]);

}

int ope(char c)

{

if(c=='+'||c=='-'||c=='*'||c=='/')

return 1;

else

return 0;

}

void main()

{

char prefix[10];

int len,val,i,opr1,opr2,res;

clrscr();

printf("Enter the prefix Expression: ");

scanf("%s",prefix);

len=strlen(prefix);

for(i=len-1;i>=0;i--)

{

switch(ope(prefix[i]))

{

case 0:

val=prefix[i];

push(val);

break;



case 1: opr1=pop();

opr2=pop();

switch(prefix[i])

{

case '+': res=opr1+opr2;

break;

case '-': res=opr1-opr2;

break;

case '*': res=opr1*opr2;

break;

case '/': res=opr1/opr2;

break;

}

push(res);



}

}

printf("Result is %d",steck[top]);

getch();

}