请问一下这段代码是数据结构的，谁能看得懂能给我解释一下？#include"stdio.h"#include"stdlib.h"#include"string.h"#include"math.h"#define true 1#define false 0#define OPSETSIZE 8typedef int Status; unsigned char Prior[8][8] ={ // 运算符优先级表// '+' '-' '*' '/' '(' ')' '#' '^'/*'+'*/'>','>','<','<','<','>','>','<',/*'-'*/'>','>','<','<','<','>','>','<',/*'*'*/'>','>','>','>','<','>','>','<',/*'/'*/'>','>','>','>','<','>','>','<',/*'('*/'<','<','<','<','<','=',' ','<',/*')'*/'>','>','>','>',' ','>','>','>',/*'#'*/'<','<','<','<','<',' ','=','<',/*'^'*/'>','>','>','>','<','>','>','>'}; typedef struct StackChar{ char c; struct StackChar *next;}SC;//StackChar类型的结点SC typedef struct StackFloat{ float f; struct StackFloat *next;}SF;//StackFloat类型的结点SF SC *Push(SC *s,char c)//SC类型的指针Push，返回p{ SC *p=(SC*)malloc(sizeof(SC)); p->c=c; p->next=s; return p;} SF *Push(SF *s,float f)//SF类型的指针Push，返回p{ SF *p=(SF*)malloc(sizeof(SF)); p->f=f; p->next=s; return p;}SC *Pop(SC *s)//SC类型的指针Pop{ SC *q=s; s=s->next; free(q); return s;} SF *Pop(SF *s)//SF类型的指针Pop{ SF *q=s; s=s->next; free(q); return s;} float Operate(float a,unsigned char theta, float b)//计算函数Operate{ switch(theta) { case '+': return a+b; case '-': return a-b; case '*': return a*b; case '/': return a/b; case '^': return pow(a,b); default : return 0; }} char OPSET[OPSETSIZE]={'+','-','*','/','(',')','#','^'}; Status In(char Test,char *TestOp){ int Find=false; for (int i=0; i< OPSETSIZE; i++) { if(Test == TestOp[i]) Find= true; } return Find;} Status ReturnOpOrd(char op,char *TestOp){ for(int i=0; i< OPSETSIZE; i++) { if (op == TestOp[i]) return i; }} char precede(char Aop, char Bop){ return Prior[ReturnOpOrd(Aop,OPSET)][ReturnOpOrd(Bop,OPSET)];} float EvaluateExpression(char* MyExpression){ // 算术表达式求值的算符优先算法 // 设OPTR和OPND分别为运算符栈和运算数栈，OP为运算符集合 SC *OPTR=NULL; // 运算符栈，字符元素 SF *OPND=NULL; // 运算数栈，实数元素 char TempData[20]; float Data,a,b; char theta,*c,Dr[]={'#','\0'}; OPTR=Push(OPTR,'#'); c=strcat(MyExpression,Dr); strcpy(TempData,"\0");//字符串拷贝函数 while (*c!= '#' || OPTR->c!='#') { if (!In(*c, OPSET)) { Dr[0]=*c; strcat(TempData,Dr); //字符串连接函数 c++; if (In(*c, OPSET)) { Data=atof(TempData); //字符串转换函数(double) OPND=Push(OPND, Data); strcpy(TempData,"\0"); } } else // 不是运算符则进栈 { switch (precede(OPTR->c, *c)) { case '<': // 栈顶元素优先级低 OPTR=Push(OPTR, *c); c++; break; case '=': // 脱括号并接收下一字符 OPTR=Pop(OPTR); c++; break; case '>': // 退栈并将运算结果入栈 theta=OPTR->c;OPTR=Pop(OPTR); b=OPND->f;OPND=Pop(OPND); a=OPND->f;OPND=Pop(OPND); OPND=Push(OPND, Operate(a, theta, b)); break; } //switch } } //while return OPND->f;} //EvaluateExpression int main(void){ char s[128]; puts("请输入表达式:"); gets(s); puts("该表达式的值为:"); printf("%s\b=%g\n",s,EvaluateExpression(s)); system("pause"); return 0;}
添加回答
举报
0/150
提交
取消