typedef struct{char s[20][20];int top;}SQ;
void copystr(char *a,char *b)
{
int i=0;
do
{
b[i]=a[i];
i++;
}
while(a[i]!='\0');
b[i]='\0';
}
void voidSQ(SQ *s)
{
s->top=-1;
}
int ifempty(SQ *s)
{
return(s->top==-1);
}
void push(SQ *S,char *c)
{
if(S->top==19)
printf("over flow\n");
else
{
S->top++;
copystr(c,S->s[S->top]);
}
}
char *pop(SQ *S)
{
if(ifempty(S))
{
printf("over flow!\n");
return(NULL);
}
else
return(S->s[S->top--]);
}
int judge(char *c)
{
if(c[1]=='\0')
switch(c[0])
{
case '+':return(3);
case '-':return(3);
case '*':return(2);
case '/':return(2);
default:return(1);
}
else
return(1);
}
void write(char *a,char *b,char *c)
{
strcat(a,c);
strcat(a,b);
}
int seek(char *c,int start)
{
int signal=1;
for(start=start++;c[start]!='\0'&&signal!=0;start++)
{
if(c[start]==')')
signal--;
else if(c[start]=='(')
signal++;
}
if(signal==0)
return(start-1);
else
{
printf("输入无效式子\n");
return(-1);
}
}
void FB(SQ *A,SQ *B)
{
for(;!ifempty(A);)
{
push(B,A->s[A->top]);
pop(A);
}
}
char *rewrite(char *A)
{
SQ front;
SQ back;
int i,j,k,flag=0;
char *result;
char mid[20];
voidSQ(&front);
voidSQ(&back);
for(i=0;A[i]!='\0';)
{
if(A[i]=='(')
{
j=seek(A,i);
for(k=i+1;k<j;k++)
{
mid[k-i-1]=A[k];
}
mid[j-i-1]='\0';
copystr(rewrite(mid),mid);
push(&back,mid);
i=j+1;
}
else if(A[i]!='(')
{
mid[0]=A[i];
mid[1]='\0';
push(&back,mid);
i++;
}
}
FB(&back,&front);
for(;front.top>=2;)
{
flag=0;
for(i=0;i<=front.top;i++)
{
if(judge(front.s[i])==2)
{
flag=1;
break;
}
}
if(flag==1)
{
for(;front.top>=2;)
{
if(judge(front.s[front.top])==1&&judge(front.s[front.top-1])==2&&judge(front.s[front.top-2])==1)
{
write(front.s[front.top],front.s[front.top-1],front.s[front.top-2]);
push(&back,front.s[front.top]);
pop(&front);
pop(&front);
pop(&front);
}
else
{
push(&back,front.s[front.top]);
pop(&front);
}
}
FB(&fr