计算器程序代码（Ｃ语言）

#include <stdio.h>

#include <conio.h>

#include <stdlib.h>

#include <string.h>

#define N 100

double numStack
={0};//操作数栈

int numTop;

char opStack
;//运算符栈

int opTop;

void print_num(double str1[],int n)

{

int i;

printf("\n操作数栈：\n");

for(i=0;i<n;i++)

printf("%g ",str1[i]);

}

void print_op(char str2[],int m)

{

int j;

printf("\n运算符栈：\n");

for(j=0;j<m;j++)

printf("%c ",str2[j]);

}

int op(char ch)//判断运算符优先级

{

if(ch=='+'||ch=='-') return 2;

if(ch=='*'||ch=='/') return 3;

if(ch=='(') return -1;

return 0;

}

double result(double num1,char op,double num2)//计算

{

if(op=='+') return num1+num2;

if(op=='-') return num1-num2;

if(op=='*') return num1*num2;

if(op=='/') return num1/num2;

return 0;

}

int compute(char str[])

{

double num=0;

int i=0,j=1,k=1;

numTop=opTop=0;

while(str[i]!='\0'||opTop>0)

{

if(str[i]>='0'&&str[i]<='9')

num=num*10+str[i]-'0';

else if( k==1&&str[i]=='-'&&(i==0||op(str[i-1])) )

k=-1;

else

{

if(i>0&&!op(str[i-1])&&str[i]!='('&&str[i-1]!=')')

{

numStack[numTop++]=num*k;

if(opTop!=0&&numTop!=0)

print_num(numStack,numTop);

num=0; j=1; k=1;

}

if(opTop==0||str[i]=='(')

{opStack[opTop++]=str[i];print_op(opStack,opTop);}

else if(str[i]==')')

{

while(opTop>0&&opStack[--opTop]!='(')

{

numStack[numTop-2]=result(numStack[numTop-2],opStack[opTop],numStack[numTop-1]);

if(opTop!=0&&numTop!=0)

{

print_num(numStack,numTop);

print_op(opStack,opTop);

}

numTop--;

}

if(opStack[opTop]!='(') return 0;

}

else

{

if(str[i]=='\0'&&numTop==0) return 0;

while(opTop>0&&op(str[i])<=op(opStack[opTop-1]))

{

numStack[numTop-2]=result(numStack[numTop-2],opStack[--opTop],numStack[numTop-1]);

if(opTop!=0&&numTop!=0)

{

print_num(numStack,numTop-1);

print_op(opStack,opTop);

}

numTop--;

}

if(str[i]!='\0')

opStack[opTop++]=str[i];

if(opTop!=0&&numTop!=0)

print_op(opStack,opTop);

}

}

if(str[i]!='\0')

i++;

}

if(numTop!=1||opTop!=0)

return 0;

return 1;

}

void menu()

{

system("cls");

printf("----------------------------------------------\n");

printf(" Again(A) | Equal(=) | Exit(E)|Introduction(I)\n");

printf("----------------------------------------------\n");

}

int main(void)

{

int i=0,j=0,k;

char str
="\0";

char num
="\0";

char save
="\0";

char ch;

double temp;

unsigned long temp2;

menu();

printf("input an expression,press key '=' to compute\n");

ch=getch();

while( 1 )

{

if(ch==')'||op(ch)||ch>='0'&&ch<='9')

{

str[i++]=ch;

str[i]='\0';

menu();

printf("input an expression,press key '=' to compute\n");

printf("%s",str);

if( ch=='-'&&(i==1||op(str[i-2]))||ch>='0'&&ch<='9' )

{

num[j++]=ch;

num[j]='\0';

}

else

j=0;

}

if(ch=='A'||ch=='a')

{

if(strlen(str))

str[--i]='\0';

menu();

printf("input an expression,press key '=' to compute\n");

printf("%s",str);

}

if(ch=='=')

{

if(compute(str))

{

printf("\n=%g\n",numStack[0]);

j=0; temp=numStack[0];

if(temp<0)

{

temp=-temp;

num[j++]='-';

num[j]='\0';

}

temp2=(unsigned long)temp;

k=1;

while(temp2/k>=10) k*=10;

while(k)

{

num[j++]=temp2/k+'0';

num[j]='\0';

temp2=temp2%k;

k/=10;

}

temp=temp-(int)temp;

if(temp!=0)

{

num[j++]='.';

num[j]='\0';

temp+=0.0000005;

}

for(k=6;k>0;k--)

{

if(temp==0) break;

temp*=10;

num[j++]=(int)temp+'0';

num[j]='\0';

temp=temp-(int)temp;

}

}

i=0; j=0; str[0]='\0';

}

if(ch=='A'||ch=='e')

{

printf("\nare you sure to quit?（Y/N）\n");

ch=getch();

if(ch=='Y'||ch=='y') break;

else

{

menu();

printf("input an expression,press key '=' to compute\n");

printf("%s",str);

}

}

ch=getch();

}

return 0;

}