C语言编一个实现简单的算术表达式求值的代码。

Posted 2023-05-17

我用编了一个简单的算术表达式求值。有一个错误"无法打开包文件 cstdio"怎么改呢
#include<cstdio>
#include<malloc.h>
#define NULL 0
typedef struct node
char date;
struct node *next;
SNode;

SNode *InitStack()
SNode *top;
top=(SNode *)malloc(sizeof(SNode));
top->next=NULL;
return top;

void PushOptr(SNode *top,char x)
SNode *p;
p=(SNode *)malloc(sizeof(SNode));
p->date=x;
p->next=top->next;
top->next=p;


char PopOptr(SNode *top)
SNode *p;
char x;
if(top==NULL)
return NULL;
p=top->next;
x=p->date;
top->next=p->next;
free(p);
return x;

void PushOpnd(SNode *top,char x)
SNode *p;
p=(SNode *)malloc(sizeof(SNode));
p->date=x;
p->next=top->next;
top->next=p;

char PopOpnd(SNode *top)
SNode *p;
char x;
if(top==NULL)
return NULL;
p=top->next;
x=p->date;
top->next=p->next;
free(p);
return x;

char GetTop(SNode *top)

return (top->next)->date;

int In(char c)
int n;
switch(c)
case '+':
case '-':
case '*':
case '/':
case '(':
case ')':
case '#':n=1;break;
default:n=0;break;

return n;

char Precede(char x,char y)
int i,j;
int form[7][7]=1,1,-1,-1,-1,1,1,1,1,-1,-1,-1,1,1,1,1,1,1,-1,1,1,1,1,1,1,-1,1,1,-1,-1,-1,-1,-1,0,2,1,1,1,1,2,1,1,-1,-1,-1,-1,-1,2,0;
switch(x)
case '+':i=0;break;
case '-':i=1;break;
case '*':i=2;break;
case '/':i=3;break;
case '(':i=4;break;
case ')':i=5;break;
case '#':i=6;break;

switch(y)
case '+':j=0;break;
case '-':j=1;break;
case '*':j=2;break;
case '/':j=3;break;
case '(':j=4;break;
case ')':j=5;break;
case '#':j=6;break;

if(form[i][j]==1)
return '>';
else
if(form[i][j]==-1)
return '<';
else
return '=';


int Operate(char x,char z,char y)
int a=x-'0',b=y-'0';
switch(z)
case '+':return a+b;
case '-':return a-b;
case '*':return a*b;
case '/':return a/b;


char Eval_Exp()
char a,b,c,r,f,z;
int result;
SNode *top[2];
top[0]=InitStack();
PushOptr(top[0],'#');
top[1]=InitStack();
c=getchar();
while(c!='#'||(GetTop(top[0]))!='#')
if(!In(c))
PushOpnd(top[1],c);
c=getchar();

else
r=Precede(GetTop(top[0]),c);
switch(r)
case '<':PushOptr(top[0],c);
c=getchar();
break;
case '=':PopOptr(top[0]);
c=getchar();
break;
case '>':b=PopOptr(top[0]);
a=PopOpnd(top[1]);
z=PopOpnd(top[1]);
result=Operate(z,b,a);
f=result+'0';
PushOpnd(top[1],f);
break;




return f;

void main()
char result;
result=Eval_Exp();
printf("%d\n",result-'0');

这个是个简单的学生管理系统,我们学校的程序大作业就是做这个...呵呵,希望能帮到你
#include<stdio.h> /*引用库函数*/
#include<stdlib.h>
#include<ctype.h>
#include<string.h>
typedef struct /*定义结构体数组*/

char num[10]; /*学号*/
char name[20]; /*姓名*/
int score; /*成绩*/
Student;
Student stu[80]; /*结构体数组变量*/
int menu_select() /*菜单函数*/

char c;
do
system("cls"); /*运行前清屏*/
printf("\t\t****Students' Grade Management System****\n"); /*菜单选择*/
printf("\t\t | 1. Input Records |\n");
printf("\t\t | 2. Display All Records |\n");
printf("\t\t | 3. Sort |\n");
printf("\t\t | 4. Insert a Record |\n");
printf("\t\t | 5. Delete a Record |\n");
printf("\t\t | 6. Query |\n");
printf("\t\t | 7. Statistic |\n");
printf("\t\t | 8. Add Records from a Text File|\n");
printf("\t\t | 9. Write to a Text file |\n");
printf("\t\t | 0. Quit |\n");
printf("\t\t*****************************************\n");
printf("\t\t\tGive your Choice(0-9):");
c=getchar(); /*读入选择*/
while(c<'0'||c>'9');
return(c-'0'); /*返回选择*/

int Input(Student stud[],int n) /*输入若干条记录*/
int i=0;
char sign,x[10]; /*x[10]为清除多余的数据所用*/
while(sign!='n'&&sign!='N') /*判断*/
printf("\t\t\tstudent's num:"); /*交互输入*/
scanf("\t\t\t%s",stud[n+i].num);
printf("\t\t\tstudent's name:");
scanf("\t\t\t%s",stud[n+i].name);
printf("\t\t\tstudent's score:");
scanf("\t\t\t%d",&stud[n+i].score);
gets(x); /*清除多余的输入*/
printf("\t\t\tany more records?(Y/N)");
scanf("\t\t\t%c",&sign); /*输入判断*/
i++;

return(n+i);

void Display(Student stud[],int n) /*显示所有记录*/

int i;
printf("\t\t\t-----------------------------------\n"); /*格式头*/
printf("\t\t\tnumber name score\n");
printf("\t\t\t-----------------------------------\n");
for(i=1;i<n+1;i++) /*循环输入*/

printf("\t\t\t%-16s%-15s%d\n",stud[i-1].num,stud[i-1].name,stud[i-1].score);
if(i>1&&i%10==0) /*每十个暂停*/
printf("\t\t\t-----------------------------------\n"); /*格式*/
printf("\t\t\t");
system("pause");
printf("\t\t\t-----------------------------------\n");


printf("\t\t\t");
system("pause");

void Sort_by_num(Student stud[],int n) /*按学号排序*/
int i,j,*p,*q,s;
char t[10];
for(i=0;i<n-1;i++) /*冒泡法排序*/
for(j=0;j<n-1-i;j++)
if(strcmp(stud[j].num,stud[j+1].num)>0)
strcpy(t,stud[j+1].num);
strcpy(stud[j+1].num,stud[j].num);
strcpy(stud[j].num,t);
strcpy(t,stud[j+1].name);
strcpy(stud[j+1].name,stud[j].name);
strcpy(stud[j].name,t);
p=&stud[j+1].score;
q=&stud[j].score;
s=*p;
*p=*q;
*q=s;


int Insert_a_record(Student stud[],int n) /*插入一条记录*/
char x[10]; /*清除多余输入所用*/
printf("\t\t\tstudent's num:"); /*交互式输入*/
scanf("\t\t\t%s",stud[n].num);
printf("\t\t\tstudent's name:");
scanf("\t\t\t%s",stud[n].name);
printf("\t\t\tstudent's score:");
scanf("\t\t\t%d",&stud[n].score);
gets(x);
n++;
Sort_by_num(stud,n); /*调用排序函数*/
printf("\t\t\tInsert Successed!\n"); /*返回成功信息*/
return(n);

int Delete_a_record(Student stud[],int n) /*按姓名查找，删除一条记录*/
char s[20];
int i=0,j;
printf("\t\t\ttell me his(her) name:"); /*交互式问寻*/
scanf("%s",s);
while(strcmp(stud[i].name,s)!=0&&i<n) i++; /*查找判断*/
if(i==n)
printf("\t\t\tnot find!\n"); /*返回失败信息*/
return(n);

for(j=i;j<n-1;j++) /*删除操作*/

strcpy(stud[j].num,stud[j+1].num);
strcpy(stud[j].name,stud[j+1].name);
stud[j].score=stud[j+1].score;

printf("\t\t\tDelete Successed!\n"); /*返回成功信息*/
return(n-1);

void Query_a_record(Student stud[],int n) /*查找并显示一个记录*/
char s[20];
int i=0;
printf("\t\t\tinput his(her) name:"); /*交互式输入*/
scanf("\t\t\t%s",s);
while(strcmp(stud[i].name,s)!=0&&i<n) i++; /*查找判断*/
if(i==n)
printf("\t\t\tnot find!\n"); /*输入失败信息*/
return;


printf("\t\t\this(her) number:%s\n",stud[i].num); /*输出该学生信息*/
printf("\t\t\this(her) score:%d\n",stud[i].score);

void Statistic(Student stud[],int n) /*新增功能，输出统计信息*/
int i,j=0,k=0,sum=0;
float aver; /*成绩平均值*/
for(i=0;i<n;i++) /*循环输入判断*/

sum+=stud[i].score;
if(stud[j].score>stud[i].score) j=i;
if(stud[k].score<stud[i].score) k=i;

aver=1.0*sum/n;
printf("\t\t\tthere are %d records.\n",n); /*总共记录数*/
printf("\t\t\tthe hignest score:\n"); /*最高分*/
printf("\t\t\tnumber:%s name:%s score:%d\n",stud[j].num,stud[j].name,stud[j].score);
printf("\t\t\tthe lowest score:\n"); /*最低分*/
printf("\t\t\tnumber:%s name:%s score:%d\n",stud[k].num,stud[k].name,stud[k].score);
printf("\t\t\tthe average score is %5.2f\n",aver); /*平均分*/

int AddfromText(Student stud[],int n) /*从文件中读入数据*/
int i=0,num;
FILE *fp; /*定义文件指针*/
char filename[20]; /*定义文件名*/
printf("\t\t\tInput the filename:");
scanf("\t\t\t%s",filename); /*输入文件名*/
if((fp=fopen(filename,"rb"))==NULL) /*打开文件*/
printf("\t\t\tcann't open the file\n"); /*打开失败信息*/
printf("\t\t\t");
system("pause");
return(n);

fscanf(fp,"%d",&num); /*读入总记录量*/
while(i<num) /*循环读入数据*/

fscanf(fp,"%s%s%d",stud[n+i].num,stud[n+i].name,&stud[n+i].score);
i++;

n+=num;
fclose(fp); /*关闭文件*/
printf("\t\t\tSuccessed!\n");
printf("\t\t\t");
system("pause");
return(n);

void WritetoText(Student stud[],int n) /*将所有记录写入文件*/

int i=0;
FILE *fp; /*定义文件指针*/
char filename[20]; /*定义文件名*/
printf("\t\t\tWrite Records to a Text File\n"); /*输入文件名*/
printf("\t\t\tInput the filename:");
scanf("\t\t\t%s",filename);
if((fp=fopen(filename,"w"))==NULL) /*打开文件*/

printf("\t\t\tcann't open the file\n");
system("pause");
return;

fprintf(fp,"%d\n",n); /*循环写入数据*/
while(i<n)

fprintf(fp,"%-16s%-15s%d\n",stud[i].num,stud[i].name,stud[i].score);
i++;

fclose(fp); /*关闭文件*/
printf("Successed!\n"); /*返回成功信息*/

void main() /*主函数*/

int n=0;
for(;;)

switch(menu_select()) /*选择判断*/

case 1:
printf("\t\t\tInput Records\n"); /*输入若干条记录*/
n=Input(stu,n);
break;
case 2:
printf("\t\t\tDisplay All Records\n"); /*显示所有记录*/
Display(stu,n);
break;
case 3:
printf("\t\t\tSort\n");
Sort_by_num(stu,n); /*按学号排序*/
printf("\t\t\tSort Suceessed!\n");
printf("\t\t\t");
system("pause");
break;
case 4:
printf("\t\t\tInsert a Record\n");
n=Insert_a_record(stu,n); /*插入一条记录*/
printf("\t\t\t");
system("pause");
break;
case 5:
printf("\t\t\tDelete a Record\n");
n=Delete_a_record(stu,n); /*按姓名查找，删除一条记录*/
printf("\t\t\t");
system("pause");
break;
case 6:
printf("\t\t\tQuery\n");
Query_a_record(stu,n); /*查找并显示一个记录*/
printf("\t\t\t");
system("pause");
break;
case 7:
printf("\t\t\tStatistic\n");
Statistic(stu,n); /*新增功能，输出统计信息*/
printf("\t\t\t");
system("pause");
break;
case 8:
printf("\t\t\tAdd Records from a Text File\n");
n=AddfromText(stu,n); /*新增功能，输出统计信息*/
break;
case 9:
printf("\t\t\tWrite to a Text file\n");
WritetoText(stu,n); /*循环写入数据*/
printf("\t\t\t");
system("pause");
break;
case 0:
printf("\t\t\tHave a Good Luck,Bye-bye!\n"); /*结束程序*/
printf("\t\t\t");
system("pause");
exit(0);


参考技术A cstdio显然是c++的头文件形式。或者 你把cstdio.改成 stdio.h或者 把文件名改成.cpp用c++去编译。 参考技术B cstdio头文件时C++的头文件，你可以把你的程序另存为*.cpp或者把头文件改成stdio.h 参考技术C ENT *bottom;
STACK;
bool calc(char *str,float *result);
float evaluationofexpression(char *str);
int main(void)

char str[50];
float result;
printf("请输入要计算的表达式：");
scanf("%s",str); 参考技术D #include<cstdio>
这里难道不要加.h吗？

C语言表达式求值

用栈结构实现

可以使用两个工作栈。一个称作OPTR,用以存放运算符；另一个称作OPND,用以存放操作数和运算结果。

大哥大姐们快来帮个忙吧。。。。

要是没人回答的话 周末给你找找看 以前写过不知道还在不
运行
按1输入表达式（不用输入＝号）
按2计算
按3输出结果
按4退出

程序如下：

#include<stdio.h>
#include <string.h>
#include <conio.h>

#define PLUS 0
#define MINUS 1
#define POWER 2
#define DIVIDE 3
#define LEFTP 4
#define RIGHP 5
#define STARTEND 6
#define DIGIT 7
#define POINT 8

#define NUM 7
#define NO 32767
#define STACKSIZE 20
char a[]='+','-','*','/','(',')','#';
int j,PriorityTable[7][7]= 1, 1,-1,-1,-1, 1, 1,
1, 1,-1,-1,-1, 1, 1,
1, 1, 1, 1,-1, 1, 1,
1, 1, 1, 1,-1, 1, 1,
-1,-1,-1,-1,-1, 0, NO,
1, 1, 1, 1,NO, 1, 1,
-1,-1,-1,-1,-1,NO, 0
;
int menu(void);
void
InputExpression(char str[])
int len;
printf("Input expression string:\n");
scanf("%s",str);
len=strlen(str);
str[len]='#';
str[len+1]='\0';

int GetCharType(char ch)
int i;
for(i=0;i<NUM;i++) if(ch==a[i]) return(i);
if(ch>='0' && ch<='9') return(DIGIT);
if(ch=='.') return(POINT);
return(-1);

int EXCUTE(char *str,double *Result)

int pp,strlength,topTr,topNd,CharType,OPTR[STACKSIZE],a;
double number,temp,OPND[STACKSIZE];

OPTR[0]=STARTEND;
topTr=1;
topNd=0;
pp=0;
while((str[pp]))
CharType=GetCharType(str[pp]);
switch(CharType)
case -1:
return(0);
case DIGIT:
number=0;
while

(str[pp]>='0' && str[pp]<='9')
number=number*10+(str[pp]-48);
pp++;

if(str[pp]=='.')
temp=10.0;
pp++;
while(str[pp]>='0' && str[pp]<='9')
number=number+(str[pp]-48)/temp;
temp=temp*10;
pp++;


OPND[topNd]=number;
topNd++;
break;
case POINT:
number=0;
temp=10.0;
pp++;
while(str[pp]>='0' && str[pp]<='9')
number=number+(str[pp]-48)/temp;
temp=temp*10;
pp++;

OPND[topNd]=number;printf("%lf",number);
topNd++;
break;

case PLUS:
case MINUS:
case POWER:
case DIVIDE:

int i;
i=PriorityTable[OPTR[topTr-1]][CharType];
if(i==-1)
OPTR[topTr]=CharType;
topTr++;

if(i==1)
while(i==1)

j=OPTR[topTr-1];
if(j==0)OPND[topNd-2]=OPND[topNd-2]+OPND[topNd-1];
if(j==1)OPND[topNd-2]=OPND[topNd-2]-OPND[topNd-1];
if(j==2)OPND[topNd-2]=OPND[topNd-2]*OPND[topNd-1];
if(j==3)OPND[topNd-2]=OPND[topNd-2]/OPND[topNd-1];
topNd--;
topTr--;
i=PriorityTable[OPTR[topTr-1]][CharType];

OPTR[topTr]=CharType;topTr++;

pp++;break;

case LEFTP:


OPTR[topTr]=LEFTP;
topTr++;pp++;
break;


case RIGHP:
while(1)
if(OPTR[topTr-1]==LEFTP)topTr--;pp++;break;
else if(OPTR[topTr-1]==STARTEND)return(0);
else
j=OPTR[topTr-1];
if(j==0)OPND[topNd-2]=OPND[topNd-2]+OPND[topNd-1];
else if(j==1)OPND[topNd-2]=OPND[topNd-2]-OPND[topNd-1];
else if(j==2)OPND[topNd-2]=OPND[topNd-2]*OPND[topNd-1];
else if(j==3)OPND[topNd-2]=OPND[topNd-2]/OPND[topNd-1];
topNd--;
topTr--;

break;


case STARTEND:

while(OPTR[topTr-1]!=STARTEND)

j=OPTR[topTr-1];
if(j==0)OPND[topNd-2]=OPND[topNd-2]+OPND[topNd-1];
else if(j==1)OPND[topNd-2]=OPND[topNd-2]-OPND[topNd-1];
else if(j==2)OPND[topNd-2]=OPND[topNd-2]*OPND[topNd-1];
else if(j==3)OPND[topNd-2]=OPND[topNd-2]/OPND[topNd-1];
topNd--;
topTr--;


if(topNd==1)
*Result=OPND[0];return(1);

else return(0);



return(1
);

void main()
int num,flag;
double result;
char str[256];
str[0]=0;
while(1)
num=menu();
switch(num)

case 1:
InputExpression(str);
flag=0;
printf("%s\n",str);
getchar();
getchar();
break;

case 2:
if(str[0]==0)
printf("Expresson is Empty!");
getchar();
break;

if(!EXCUTE(str,&result))
printf("The expression has error!\n");
getchar();

else
printf("calulation has finished!\n");
getchar();
flag=1;

break;
case 3:
if(flag)
printf("#%s=%lf\n",str,result);
getchar();
getchar();

break;
case 4:
break;

if(num==4) break;


int menu(void)
int num;
clrscr();
printf("%20c1--input expression\n",' ');
printf("%20c2--calculation expression\n",' ');
printf("%20c3--print result\n",' ');
printf("%20c4--Quit\n",' ');
printf(" please select 1,2,3,4:");
do
scanf("%d",&num);
while(num<1 || num>4);
return(num);

参考资料：LDCQ

参考技术A 按照数据结构书上写的，用算符优先算法就可以了，很简单！