stackdouble.c

This program use for ExpEvaluation

#define TRUE 1
#define FALSE 0
#define STACK_SIZE 50   /*stack at most 50 elem*/
#define TYPE float
typedef struct {
        TYPE  elem[STACK_SIZE];
        int top;
}seqstack1;

void Initstack1(seqstack1 *S){
     S->top=-1;
}

int Push1(seqstack1 *S,  TYPE  x){
    if (S->top==STACK_SIZE)
        return(FALSE);      /*stack is full*/
    S->top++;
    S->elem[S->top] = x;
    return (TRUE);
}

int Pop1(seqstack1 *S, TYPE  *x){
    if(S->top==-1)
       return(FALSE);   /*stack is empty*/
    *x=S->elem[S->top];
    S->top--;
    return (TRUE);
}

float Gettop1(seqstack1 *S){
    TYPE  x;
    if(S->top==-1)
       printf("There is no element!\n");
    x=S->elem[S->top];
    return x;
}