C语言加减乘除 | 易学教程

#define _CRT_SECURE_NO_WARNINGS
#include <cstdlib>
#include <stdio.h>
#include <string.h>

int main()
{
   float a, b, c;
   char str[100]; //输入的字符串
   char preStr[100];//运算符前的字符串
   char endStr[100];//运算符后面的字符串
   //scanf("%f%c%f", &a, &x, &b);
   printf("请输入字符串：");
   scanf("%s", str); /*输入参数是已经定义好的“字符数组名”, 不用加&, 因为在C语言中数组名就代表该数组的起始地址*/
   int index = -1;
   for (int i = 0; i < strlen(str); i++)//确定运算符的位置
   {
       switch (str[i])
       {
       case'+':index = i; break;
       case'-':index = i; break;
       case'*':index = i; break;
       case'/':index = i; break;
       }

       if (index != -1)
       {
           break;
       }
   }

   for (int i = 0; i < index; i++)//遍历运算符前面的字符串
   {
       preStr[i] = str[i];
   }
   preStr[index] = '\0';

   for (int i = index + 1; i < strlen(str); i++)//遍历运算符后面的字符串
   {
       endStr[i- index-1] = str[i];
   }
   endStr[strlen(str)-index - 1] = '\0';

   //字符串转数字
   a = atoi(preStr);
   b = atoi(endStr);
   switch (str[index])//开始运算
   {
   case'+':c = a + b; break;
   case'-':c = a - b; break;
   case'*':c = a * b; break;
   case'/':c = a / b; break;
   }
   printf("输出结果：%f\n", c);

}

来源：CSDN

作者：yy990928

链接：https://blog.csdn.net/yy990928/article/details/104674983

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c语言