struct s_node
{
int data
struct s_node *next
}
typedef struct s_node s_list
typedef s_list *link
link operator=NULL
link operand=NULL
link push(link stack,int value)
{
link newnode
newnode=(link) malloc(sizeof(s_list))
if(!newnode)
{
printf("\nMemory allocation failure!!!")
return NULL
}
newnode->data=value
newnode->next=stack
stack=newnode
return stack
}
link pop(link stack,int *value)
{
link top
if(stack !=NULL)
{
top=stack
stack=stack->next
*value=top->data
free(top)
return stack
}
else
*value=-1
}
int empty(link stack)
{
if(stack==NULL)
return 1
else
return 0
}
int is_operator(char operator)
{
switch (operator)
{
case '+': case '-': case '*': case '/': return 1
default:return 0
}
}
int priority(char operator)
{
switch(operator)
{
case '+': case '-' : return 1
case '*': case '/' : return 2
default: return 0
}
}
int two_result(int operator,int operand1,int operand2)
{
switch(operator)
{
case '+':return(operand2+operand1)
case '-':return(operand2-operand1)
case '*':return(operand2*operand1)
case '/':return(operand2/operand1)
}
}
void main()
{
char expression[50]
int position=0
int op=0
int operand1=0
int operand2=0
int evaluate=0
printf("\nPlease input the inorder expression:")
gets(expression)
while(expression[position]!='\0'&&expression[position]!='\n')
{
if(is_operator(expression[position]))
{
if(!empty(operator))
while(priority(expression[position])<= priority(operator->data)&&
!empty(operator))
{
operand=pop(operand,&operand1)
operand=pop(operand,&operand2)
operator=pop(operator,&op)
operand=push(operand,two_result(op,operand1,operand2))
}
operator=push(operator,expression[position])
}
else
operand=push(operand,expression[position]-48)
position++
}
while(!empty(operator))
{
operator=pop(operator,&op)
operand=pop(operand,&operand1)
operand=pop(operand,&operand2)
operand=push(operand,two_result(op,operand1,operand2))
}
operand=pop(operand,&evaluate)
printf("The expression [%s] result is '%d' ",expression,evaluate)
getch()
}
#include<stdio.h>int main()
{
double num1
double num2
double result
char ch
printf("Please enter express to caculate, 'q' to exit(eg. 1+3):")
while(scanf("%lf%c%lf",&num1,&ch,&num2) == 3)
{
switch(ch)
{
case '+':
{
result = num1 + num2
break
}
case '-':
{
result = num1 - num2
break
}
case '/':
{
if(num2 == 0)
printf("Error:div/0\n")
else
result = num1 / num2
break
}
case '*':
{
result = num1 * num2
break
}
}
printf("%g%c%g=%g\n",num1,ch,num2,result)
printf("Please enter express to caculate, 'q' to exit(eg. 1+3):")
}
return 0
}
