习题3.18 检测平衡符号（/* */ 不知怎么做）

/* 检测平衡符号 */

#include<stdio.h>

#include<stdlib.h>



struct stack;

typedef struct stack * PtrToStack;

struct stack{

    char *Array;

    int TopOfStack;

    int Capacity;

};

PtrToStack

CreateStack( int MaxSize )

{

    PtrToStack p;

    p = malloc(sizeof(struct stack));

    p->Array = malloc(sizeof(char) * MaxSize );

    p->Capacity = MaxSize;

    p->TopOfStack = -1;

    return p;

}

int

IsEmpty( PtrToStack s)

{

    return s->TopOfStack == -1;

}

void

Pop( PtrToStack s )

{

    if( !IsEmpty( s ) )

        s->TopOfStack--;

    else

        printf("error");

}

char

Top( PtrToStack s )

{

    if( !IsEmpty( s ) )

        return s->Array[s->TopOfStack];

    else

        printf("error");

}



int

IsFull( PtrToStack s )

{

    return s->TopOfStack == s->Capacity-1;

}



void

Push( char ch, PtrToStack s)

{

    if( !IsFull(s) )

        s->Array[++s->TopOfStack] = ch;

    else

        printf("error");

}

//遇到开放符号栈空，遇到开放符号不匹配，读入完成，栈不空

int main()

{

    int MaxSize = 10;

    char tmp;

    PtrToStack s;

    s = CreateStack( MaxSize );

    while( ( tmp = getchar() ) != '#' )

    {

        if( tmp == '(' || tmp == '{' || tmp == '[')

            Push( tmp, s );

        else

        {

            if( IsEmpty(s) ){

                printf("error1");

                return 0;

            }

            else

            {

                switch( tmp )

                {

                    case ']':

                        if(Top(s) != '[')

                        {

                            printf("error2");

                            return 0;

                        }

                        break;

                    case ')':

                        if(Top(s) != '(' )

                        {

                            printf("error2");

                            return 0;

                        }

                        break;

                    case '}':

                        if(Top(s) != '{')

                        {

                            printf("error2");

                            return 0;

                        }

                        break;

                }//switch

                Pop(s);

            }//else

        }//else

    }//while

    if(s->TopOfStack != -1)

    {

        printf("error3");

        return 0;

    }

}

View Code

 注意该算法3个error：1.读到封闭符号时，栈空error1

　　　　　　　　　　 2.读到#栈非空error2

　　　　　　　　　　3.读到封闭符号，栈非空，可是不对应error3