Completely Solved C, C++ Programs Assignment.




Data structure(Infix,Prefix,Postfix)-PART 4

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C Code  for Infix to Postfix:
int find (const apvector &list, double target)#include 
#include 
#include 
#define MAX 10
#define EMPTY -1
struct stack
{
char data[MAX];
int top;
};
int isempty(struct stack *s)
{
return (s->top == EMPTY) ? 1 : 0;
}
void emptystack(struct stack* s)
{
s->top=EMPTY;
}
void push(struct stack* s,int item)
{
if(s->top == (MAX-1))
{
printf("\nSTACK FULL");
}
else
{
++s->top;
s->data[s->top]=item;
}
}
char pop(struct stack* s)
{
char ret=(char)EMPTY;
if(!isempty(s))
{
ret= s->data[s->top];
--s->top;
}
return ret;
}
void display(struct stack s)
{
while(s.top != EMPTY)
{
printf("\n%d",s.data[s.top]);
s.top--;
}
}
int isoperator(char e)
{
if(e == '+' || e == '-' || e == '*' || e == '/' || e == '%')
return 1;
else
return 0;
}
int priority(char e)
{
int pri = 0;
if(e == '*' || e == '/' || e =='%')
pri = 2;
else
{
if(e == '+' || e == '-')
pri = 1;
}
return pri;
}
void infix2postfix(char* infix, char * postfix, int insertspace)
{
char *i,*p;
struct stack X;
char n1;
emptystack(&X);
i = &infix[0];
p = &postfix[0];
while(*i)
{
while(*i == ' ' || *i == '\t')
{
i++;
}
if( isdigit(*i) || isalpha(*i) )
{
while( isdigit(*i) || isalpha(*i))
{
*p = *i;
p++;
i++;
}
/*SPACE CODE*/
if(insertspace)
{
*p = ' ';
p++;
}
/*END SPACE CODE*/
}
if( *i == '(' )
{
push(&X,*i);
i++;
}
if( *i == ')')
{
n1 = pop(&X);
while( n1 != '(' )
{
*p = n1;
p++;
/*SPACE CODE*/
if(insertspace)
{
*p = ' ';
p++;
}
                                                      /*END SPACE CODE*/
n1 = pop(&X);
}
i++;
}
if( isoperator(*i) )
{
if(isempty(&X))
push(&X,*i);
else
{
n1 = pop(&X);
while(priority(n1) >= priority(*i))
{
*p = n1;
p++;
/*SPACE CODE*/
if(insertspace)
{
*p = ' ';
p++;
}
                                                          /*END SPACE CODE*/
n1 = pop(&X);
}
push(&X,n1);
push(&X,*i);
}
i++;
}
}
while(!isempty(&X))
{
n1 = pop(&X);
*p = n1;
p++;
/*SPACE CODE*/
if(insertspace)
{
*p = ' ';
p++;
}
/*END SPACE CODE*/
}
*p = '\0';
}
int main()
{
char in[50],post[50];
strcpy(&post[0],"");
printf("Enter Infix Expression : ");
fflush(stdin);
gets(in);
infix2postfix(&in[0],&post[0],1);
printf("Postfix Expression is : %s\n",&post[0]);
return 0;
}
           /*        SAMPLE OUTPUT:
Enter Infix Expression : A + B + C / (E - F)
Postfix Expression is : A B + C E F - / +         */


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