c语言实现利用栈的计算器（含大于9的数，小数和负数）
1、效果
输入数学表达式 输入为数字 和“+ – * / ^(平方) r（根号）s（sin) c(cos) t(tan) l(ln)以及括号”，得到算式的答案
2、思路
（1）识别大于9的数，小数和负数
（2）改写为后缀表达式
（3）用后缀表达式进行计算
3.实现
（1）识别大于9的数，小数和负数，
buf为接收输入的字符串
formed为存放后缀表达式的double类型数组
//根据int数组计算实际的值
double cal(int* arr, int flag)
{
double num = 0;
int i = 0;
int j = 0;
for (i = 0; i < flag; i++)
{
if (arr[i] == '.')
break;
}
if (i + 1 == flag)//无小数点
{
for (j = 0; j < flag; j++)
num = num + (arr[j] * pow(10, i--));
}
else
{
for (j = 0; j < flag; j++)
{
if (arr[j] != '.')
num = num + (arr[j] * pow(10, --i));
}
}
return num;
}
//识别负数并将负号改为后缀‘f'
if (buf[i] == '-' && !(buf[i - 1] > 47 && buf[i - 1] < 58) && buf[i - 1] != ')'&&!(buf[i-1] == '^' || buf[i-1] == 'r' || buf[i-1] == 's' || buf[i-1] == 'c' || buf[i-1] == 'l' || buf[i-1] == 't' || buf[i-1] == 'f'))
{
k = strlen(buf + 1) + 1;
if (buf[i + 1] == '(')
{
m = 1;
for (l = i+2; 1; l++)
{
if (buf[l] == ')')
{
m--;
}
if (buf[l] == '(')
{
m++;
}
if (m == 0)
break;
}
for (k = k; k-1 > l; k--)
{
buf[k] = buf[k - 1];
}
buf[l + 1] = 'f';
}
else
{
for(l=i+1;(buf[l] > 47 && buf[l ] < 58)||buf[l]=='.' || buf[l] == 'e' || buf[l] == 'p';l++)
for (k = k; k-1 > l; k--)
{
buf[k] = buf[k - 1];
}
buf[l] = 'f';
}
continue;
}
//将buf中的数存放至int数组中，再将int数组代表的数存入formed
//'0'的asc码值为48，'9'为58，'.'为46
int flag==0;
for (i = 0; i < max - 1; i++)
{
if (buf[i] > 47 && buf[i] < 58)
{
arr[flag] = ((int)buf[i] - 48);
flag++;
again:
if (buf[i + 1] > 47 && buf[i + 1] < 58)
{
arr[flag] = (int)buf[i + 1] - 48;
i++;
flag++;
goto again;
}
else if (buf[i + 1] == 46)
{
arr[flag] = buf[i + 1];
i++;
flag++;
goto again;
}
else
{
formed[f] = cal(arr, flag);
f++;
flag = 0;
memset(arr, 0, sizeof(arr));
}
}
（2）后缀表达式实现
这里运算符加0.00005的原因是会遇到与运算符asc码值相同的数，加0.00005会避免大多数的bug
typedef struct stack
{
double data[max];
int top;
}stack;
void jinzhan(stack* p, char a)
{
if (p->top < (max - 1))
{
p->data[p->top] = a;
p->top++;
}
else
printf("errorjin\n");
}
double chuzhan(stack* p)
{
if (p->top > 0)
{
p->top--;
return p->data[p->top];
}
else
printf("errorchu\n");
}
int f=0;
int flag=0;
stack* p = (stack*)malloc(sizeof(stack));
for (i = 0; i < max - 1; i++)
{
if (buf[i] > 47 && buf[i] < 58)
{
arr[flag] = ((int)buf[i] - 48);
flag++;
again:
if (buf[i + 1] > 47 && buf[i + 1] < 58)
{
arr[flag] = (int)buf[i + 1] - 48;
i++;
flag++;
goto again;
}
else if (buf[i + 1] == 46)
{
arr[flag] = buf[i + 1];
i++;
flag++;
goto again;
}
else
{
formed[f] = cal(arr, flag);
f++;
flag = 0;
memset(arr, 0, sizeof(arr));
}
}
else if (buf[i] == 'p')
{
formed[f] = 3.141592653589793238;
f++;
}
else if (buf[i] == 'e')
{
formed[f] = 2.718281828459;
f++;
}
else if (buf[i] == '(')
{
jinzhan(p, buf[i]);
}
else if (buf[i] == ')')
{
while ((a = chuzhan(p)) != '(' && p->top > 0)
{
formed[f] = (a + 0.00005);
f++;
}
}
else if (buf[i] == '+' || buf[i] == '-')
{
while (1)
{
if (p->data[p->top - 1] != 40 && p->top > 0)
{
formed[f] = chuzhan(p) + 0.00005;
f++;
}
else
break;
}
jinzhan(p, buf[i]);
}
else if (buf[i] == '*' || buf[i] == '/')
{
while (1)
{
if (p->data[p->top - 1] != '+' && p->data[p->top - 1] != '-' && p->top > 0 && p->data[p->top - 1] != '(')
{
formed[f] = chuzhan(p) + 0.00005;
f++;
}
else
break;
}
jinzhan(p, buf[i]);
}
else if (buf[i] == '^' || buf[i] == 'r' || buf[i] == 's' || buf[i] == 'c' || buf[i] == 'l' || buf[i] == 't')
{
while (1)
{
if (p->data[p->top - 1] != '+' && p->data[p->top - 1] != '-' && p->top > 0 && p->data[p->top - 1] != '(' && p->data[p->top - 1] != '*' && p->data[p->top - 1] != '/')
{
formed[f] = chuzhan(p) + 0.00005;
f++;
}
else
break;
}
jinzhan(p, buf[i]);
}
else if (buf[i] == ' ')
continue;
else if (buf[i] == '\0')
continue;
else
printf("errorp");
}
while (p->top > 0)//将剩余的运算符全部弹出，存入formed
{
formed[f] = chuzhan(p) + 0.00005;
f++;
}
}
（3）用后缀表达式进行计算
typedef struct stackd
{
double data[max];
int top;
}stackd;
void jinzhand(stackd* p, double a)
{
if (p->top < (max - 1))
{
p->data[p->top] = a;
p->top++;
}
else
printf("errorjind\n");
}
double chuzhand(stackd* p)
{
if (p->top >0)
{
p->top--;
return p->data[p->top];
}
else
printf("errorchud\n");
}
stack* pp = (stackd*)malloc(sizeof(stackd));
for (i = 0; i < max - 1; i++)
{
if (formed[i] == '+' + 0.00005)
{
n1 = (double)chuzhand(pp);
n2 = (double)chuzhand(pp);
n3 = n1 + n2;
jinzhand(pp, n3);
}
else if (formed[i] == '-' + 0.00005)
{
n1 = (double)chuzhand(pp);
n2 = (double)chuzhand(pp);
n3 = n2 - n1;
jinzhand(pp, n3);
}
else if (formed[i] == '*' + 0.00005)
{
n1 = (double)chuzhand(pp);
n2 = (double)chuzhand(pp);
n3 = n2 * n1;
jinzhand(pp, n3);
}
else if (formed[i] == '/' + 0.00005)
{
n1 = (double)chuzhand(pp);
n2 = (double)chuzhand(pp);
n3 = n2 / n1;
jinzhand(pp, n3);
}
else if (formed[i] == '^' + 0.00005)
{
n1 = (double)chuzhand(pp);
n1 = n1 * n1;
jinzhand(pp, n1);
}
else if (formed[i] == 'r' + 0.00005)
{
n1 = (double)chuzhand(pp);
n1 = sqrt(n1);
jinzhand(pp, n1);
}
else if (formed[i] == 's' + 0.00005)
{
n1 = (double)chuzhand(pp);
n1 = sin(n1);
jinzhand(pp, n1);
}
else if (formed[i] == 'c' + 0.00005)
{
n1 = (double)chuzhand(pp);
n1 = cos(n1);
jinzhand(pp, n1);
}
else if (formed[i] == 'l' + 0.00005)
{
n1 = (double)chuzhand(pp);
n1 = log(n1);
jinzhand(pp, n1);
}
else if (formed[i] == 't' + 0.00005)
{
n1 = (double)chuzhand(pp);
n1 = tan(n1);
jinzhand(pp, n1);
}
else if (formed[i] == ' ' + 0.00005)
continue;
else if (formed[i] == '\0' + 0.00005)
continue;
else
{
jinzhand(pp, formed[i]);
}
}
计算结束后，stackd中应只剩data[0],我们
printf("%lf\n", pp->data[0]);
得到最终结果
全部代码
#include<stdio.h>
#include<string.h>
#include<memory.h>
#include<stdlib.h>
#include<Windows.h>
#include<math.h>
#define max 50
typedef struct stack
{
double data[max];
int top;
}stack;
typedef struct stackd
{
double data[max];
int top;
}stackd;
void jinzhan(stack* p, char a)
{
if (p->top < (max - 1))
{
p->data[p->top] = a;
p->top++;
}
else
printf("errorjin\n");
}
double chuzhan(stack* p)
{
if (p->top > 0)
{
p->top--;
return p->data[p->top];
}
else
printf("errorchu\n");
}
void jinzhand(stackd* p, double a)
{
if (p->top < (max - 1))
{
p->data[p->top] = a;
p->top++;
}
else
printf("errorjind\n");
}
double chuzhand(stackd* p)
{
if (p->top >0)
{
p->top--;
return p->data[p->top];
}
else
printf("errorchud\n");
}
double cal(int* arr, int flag)
{
double num = 0;
int i = 0;
int j = 0;
for (i = 0; i < flag; i++)
{
if (arr[i] == '.')
break;
}
if (i + 1 == flag)//wudian
{
for (j = 0; j < flag; j++)
num = num + (arr[j] * pow(10, i--));
}
else
{
for (j = 0; j < flag; j++)
{
if (arr[j] != '.')
num = num + (arr[j] * pow(10, --i));
}
}
return num;
}
int main()
{
while (1)
{
printf("示例：(ps+pc+pt+el)^-((1+2)*4/3)r=-2\n");
int flag = 0;
int flag2 = 0;
int arr[max];
memset(arr, 0, sizeof(arr));
double a;
int f = 0;
int m,j,k;
double formed[max];
char buf[max];
int i = 0;
double n1 = 0;
double n2 = 0;
double n3 = 0;
memset(buf, 0, sizeof(buf));
memset(formed, 0, sizeof(formed));
stack* p = (stack*)malloc(sizeof(stack));
stackd* pp = (stackd*)malloc(sizeof(stackd));
pp->top = 0;
memset(p->data, 0, sizeof(p->data));
memset(pp->data, 0, sizeof(pp->data));
if (p)
{
p->top = 0;
scanf("%s", buf);
for (i = 0; i < max - 1; i++)
{
if (buf[i] > 47 && buf[i] < 58)
{
arr[flag] = ((int)buf[i] - 48);
flag++;
again:
if (buf[i + 1] > 47 && buf[i + 1] < 58)
{
arr[flag] = (int)buf[i + 1] - 48;
i++;
flag++;
goto again;
}
else if (buf[i + 1] == 46)
{
arr[flag] = buf[i + 1];
i++;
flag++;
goto again;
}
else
{
formed[f] = cal(arr, flag);
f++;
flag = 0;
memset(arr, 0, sizeof(arr));
}
}
else if (buf[i] == 'p')
{
formed[f] = 3.141592653589793238;
f++;
}
else if (buf[i] == 'e')
{
formed[f] = 2.718281828459;
f++;
}
else if (buf[i] == '(')
{
jinzhan(p, buf[i]);
}
else if (buf[i] == ')')
{
while ((a = chuzhan(p)) != '(' && p->top > 0)
{
formed[f] = (a + 0.00005);
f++;
}
}
else if (buf[i] == '+' || buf[i] == '-')
{
if (buf[i] == '-' && !(buf[i - 1] > 47 && buf[i - 1] < 58) && buf[i - 1] != ')'&&!(buf[i-1] == '^' || buf[i-1] == 'r' || buf[i-1] == 's' || buf[i-1] == 'c' || buf[i-1] == 'l' || buf[i-1] == 't' || buf[i-1] == 'f'))
{
k = strlen(buf + 1) + 1;
if (buf[i + 1] == '(')
{
m = 1;
for (l = i+2; 1; l++)
{
if (buf[l] == ')')
{
m--;
}
if (buf[l] == '(')
{
m++;
}
if (m == 0)
break;
}
for (k = k; k-1 > l; k--)
{
buf[k] = buf[k - 1];
}
buf[l + 1] = 'f';
}
else
{
for(l=i+1;(buf[l] > 47 && buf[l ] < 58)||buf[l]=='.' || buf[l] == 'e' || buf[l] == 'p';l++)
for (k = k; k-1 > l; k--)
{
buf[k] = buf[k - 1];
}
buf[l] = 'f';
}
continue;
}
while (1)
{
if (p->data[p->top - 1] != 40 && p->top > 0)
{
formed[f] = chuzhan(p) + 0.00005;
f++;
}
else
break;
}
jinzhan(p, buf[i]);
}
else if (buf[i] == '*' || buf[i] == '/')
{
while (1)
{
if (p->data[p->top - 1] != '+' && p->data[p->top - 1] != '-' && p->top > 0 && p->data[p->top - 1] != '(')
{
formed[f] = chuzhan(p) + 0.00005;
f++;
}
else
break;
}
jinzhan(p, buf[i]);
}
else if (buf[i] == '^' || buf[i] == 'r' || buf[i] == 's' || buf[i] == 'c' || buf[i] == 'l' || buf[i] == 't')
{
while (1)
{
if (p->data[p->top - 1] != '+' && p->data[p->top - 1] != '-' && p->top > 0 && p->data[p->top - 1] != '(' && p->data[p->top - 1] != '*' && p->data[p->top - 1] != '/')
{
formed[f] = chuzhan(p) + 0.00005;
f++;
}
else
break;
}
jinzhan(p, buf[i]);
}
else if (buf[i] == ' ')
continue;
else if (buf[i] == '\0')
continue;
else
printf("errorp");
}
while (p->top > 0)
{
formed[f] = chuzhan(p) + 0.00005;
f++;
}
}
for (i = 0; i < max - 1; i++)
{
if (formed[i] == '+' + 0.00005)
{
n1 = (double)chuzhand(pp);
n2 = (double)chuzhand(pp);
n3 = n1 + n2;
jinzhand(pp, n3);
}
else if (formed[i] == '-' + 0.00005)
{
n1 = (double)chuzhand(pp);
n2 = (double)chuzhand(pp);
n3 = n2 - n1;
jinzhand(pp, n3);
}
else if (formed[i] == '*' + 0.00005)
{
n1 = (double)chuzhand(pp);
n2 = (double)chuzhand(pp);
n3 = n2 * n1;
jinzhand(pp, n3);
}
else if (formed[i] == '/' + 0.00005)
{
n1 = (double)chuzhand(pp);
n2 = (double)chuzhand(pp);
n3 = n2 / n1;
jinzhand(pp, n3);
}
else if (formed[i] == '^' + 0.00005)
{
n1 = (double)chuzhand(pp);
n1 = n1 * n1;
jinzhand(pp, n1);
}
else if (formed[i] == 'r' + 0.00005)
{
n1 = (double)chuzhand(pp);
n1 = sqrt(n1);
jinzhand(pp, n1);
}
else if (formed[i] == 's' + 0.00005)
{
n1 = (double)chuzhand(pp);
n1 = sin(n1);
jinzhand(pp, n1);
}
else if (formed[i] == 'c' + 0.00005)
{
n1 = (double)chuzhand(pp);
n1 = cos(n1);
jinzhand(pp, n1);
}
else if (formed[i] == 'l' + 0.00005)
{
n1 = (double)chuzhand(pp);
n1 = log(n1);
jinzhand(pp, n1);
}
else if (formed[i] == 't' + 0.00005)
{
n1 = (double)chuzhand(pp);
n1 = tan(n1);
jinzhand(pp, n1);
}
else if (formed[i] == ' ' + 0.00005)
continue;
else if (formed[i] == '\0' + 0.00005)
continue;
else
{
jinzhand(pp, formed[i]);
}
}
printf("%lf\n", pp->data[0]);
system("pause");
}
return 0;
}
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