题解 | #实现简单计算器功能#

#include <cstdlib>
#include <iostream>
using namespace std;
#include <cstring>
#include <sstream>

int main() {

    char str[100] = { 0 };
    cin.getline(str, sizeof(str));

    // write your code here......
    string oper;
    string sr1, sr2;
    int s = 0;
    for (int i = 0; i < strlen(str); i++)
    {
        if (!isspace(str[i]))
        {
            if (s == 0)
            {
                oper += str[i];
            }
            else if (s == 1)
            {
                sr1 += str[i];
            }
            else
            {
                sr2 += str[i];
            }
        }
        else
        {
            s += 1;
        }
    }

    stringstream ss;
    int r1 = stoi(sr1);
    int r2 = stoi(sr2);

    if (-100 <= r1 && r1 <= 100 && -100 <= r2 && r2 <= 100)
    {
        if (!strcasecmp(oper.c_str(), "add"))
        {
            cout << r1 + r2 << endl;
        }
        else if (!strcasecmp(oper.c_str(), "sub"))
        {
            cout << r1 - r2 << endl;
        }
        else if (!strcasecmp(oper.c_str(), "mul"))
        {
            cout << r1 * r2 << endl;
        }
        else if (!strcasecmp(oper.c_str(), "div"))
        {  
            if (r2 == 0)
            {
                cout << "Error" << endl;
            }
            else
            {
                cout << r1 / r2 << endl;
            }
        }
   }

    return 0;
}