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postev
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postev
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#include<stdio.h>
#include<ctype.h>
#define max 100
float st[max];
int top=-1;
void push(float st[], float val);
float pop (float st[]);
float evaluatepostfix(char exp[]);
int main()
{
float val;
char exp[100];
printf("\n Enter your postfix expression");
scanf("%s",exp);
val=evaluatepostfix(exp);
printf("\n value of postfix expression is %0.2f",val);
}
float evaluatepostfix(char exp[])
{
int i=0;
float op1,op2,value;
while(exp[i]!='\0')
{
if(isdigit(exp[i]))
push(st,(float)(exp[i]-'0'));
else
{
op2=pop(st);
op1=pop(st);
switch(exp[i])
{
case '+': value = op1 + op2;
break;
case '-': value = op1 - op2;
break;
case '*': value= op1 * op2;
break;
case '/': value = op1/op2;
break;
case '%': value = (int)op1 % (int)op2;
break;
}
push(st,value);
}
i++;
}
return(pop(st));
}
void push(float st[], float val)
{
if(top==max-1)
printf("\n stack overflow!!\n");
else
{
top++;
st[top]=val;
}
}
float pop(float st[])
{
float val = -1;
if(top==-1)
printf("\n stack overflow\n");
else
{
val = st[top];
top--;
}
return val;
}