小甲鱼老师中缀表达式转后缀表达式的代码好像错了
本帖最后由 narutoxyl 于 2014-3-27 15:54 编辑如果输入 12*(6-3)+6/2*3# 的话 结果是 12 6 3 - * 6 2 3 * / +
但正确的应该是12 6 3 - * 6 2 / 3 * +
度娘了一下,是不是遇上*或/时,如果栈顶是*/,也要pop啊??
#include <stdio.h>
#include <stdlib.h>
#define STACK_INIT_SIZE 20
#define STACKINCREMENT10
typedef char ElemType;
typedef struct
{
ElemType *base;
ElemType *top;
int stackSize;
}sqStack;
InitStack(sqStack *s)
{
s->base = (ElemType *)malloc(STACK_INIT_SIZE * sizeof(ElemType));
if( !s->base )
exit(0);
s->top = s->base;
s->stackSize = STACK_INIT_SIZE;
}
Push(sqStack *s, ElemType e)
{
// 栈满,追加空间,鱼油必须懂!
if( s->top - s->base >= s->stackSize )
{
s->base = (ElemType *)realloc(s->base, (s->stackSize + STACKINCREMENT) * sizeof(ElemType));
if( !s->base )
exit(0);
s->top = s->base + s->stackSize;
s->stackSize = s->stackSize + STACKINCREMENT;
}
*(s->top) = e; // 存放数据
s->top++;
}
Pop(sqStack *s, ElemType *e)
{
if( s->top == s->base )
return;
*e = *--(s->top); // 将栈顶元素弹出并修改栈顶指针
}
int StackLen(sqStack s)
{
return (s.top - s.base);
}
int main()
{
sqStack s;
char c, e;
InitStack( &s );
printf("请输入中缀表达式,以#作为结束标志:");
scanf("%c", &c);
while( c != '#' )
{
while( c>='0' && c<='9' )
{
printf("%c", c);
scanf("%c", &c);
if( c<'0' || c>'9' )
{
printf(" ");
}
}
if( ')' == c )
{
Pop(&s, &e);
while( '(' != e )
{
printf("%c ", e);
Pop(&s, &e);
}
}
else if( '+'==c || '-'==c )
{
if( !StackLen(s) )
{
Push(&s, c);
}
else
{
do
{
Pop(&s, &e);
if( '(' == e )
{
Push(&s, e);
}
else
{
printf("%c ", e);
}
}while( StackLen(s) && '('!=e );
Push(&s, c);
}
}
else if( '*'==c || '/'==c || '('==c )
{
Push(&s, c);
}
else if( '#'== c )
{
break;
}
else
{
printf("\n出错:输入格式错误!\n");
return -1;
}
scanf("%c", &c);
}
while( StackLen(s) )
{
Pop(&s, &e);
printf("%c ", e);
}
return 0;
}
把109行*和/的情况改成这样好像可以了,求大神指点!else if( '*'==c || '/'==c )
{
if(StackLen(s))
{
Pop(&s,&e);
while('('!=e&&'+'!=e&&'-'!=e)
{
printf("%c ",e);
Pop(&s,&e);
}
Push(&s,e);
}
Push(&s,c);
}
else if('('==c)
{
Push(&s,c);
} narutoxyl 发表于 2014-3-27 15:40
把109行*和/的情况改成这样好像可以了,求大神指点!
没错啊,我用VC6.0运行得了 他源代码那里确实错了! 的确是错了 我也觉得是,因为如果碰见连续的除法,他的算法就是先把后面的是先把后面的除法计算了,顺序不对
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