@[ming0819](/user/489854)
```c++
//P1957 口算练习题
#include <iostream>
#include <algorithm>
#include <vector>
#include <cmath>
#include <cstdio>
#include <cstring>
using namespace std;
const int N = 100010;
int nsize(int n) // 计算一个数字的大小
{
if (n == 0)
return 1;
int i = 0;
if (n < 0)
n = 0 - n, i++;
while (n >= 1)
{
n /= 10;
++i;
}
return i;
}
int change(string a) //从字符串转为数字
{
int n = 0;
for (int i = 0; i < a.size(); ++i)
n += (a[i] - '0') * pow(10, a.size()-i-1);
return n;
}
int main()
{
int n;
cin >> n;
char op;
for (int i = 0; i < n; ++i)
{
string s;
cin >> s;
if (s[0] >= 'a' && s[0] <= 'c')
{
op = s[0];
int a, b;
cin >> a >> b;
if (op == 'a')
{
printf("%d+%d=%d\n", a, b, a+b);
cout << 2+nsize(a)+nsize(b)+nsize(a+b) << endl;
}
else if (op == 'b')
{
printf("%d-%d=%d\n", a, b, a-b);
cout << 2+nsize(a)+nsize(b)+nsize(a-b) << endl;
}
else
{
printf("%d*%d=%d\n", a, b, a*b);
cout << 2+nsize(a)+nsize(b)+nsize(a*b) << endl;
}
}
else
{
int a = change(s);
int b;
cin >> b;
if (op == 'a')
{
printf("%d+%d=%d\n", a, b, a+b);
cout << 2+nsize(a)+nsize(b)+nsize(a+b) << endl;
}
else if (op == 'b')
{
printf("%d-%d=%d\n", a, b, a-b);
cout << 2+nsize(a)+nsize(b)+nsize(a-b) << endl;
}
else
{
printf("%d*%d=%d\n", a, b, a*b);
cout << 2+nsize(a)+nsize(b)+nsize(a*b) << endl;
}
}
}
return 0;
}
```
by Jasper08 @ 2022-03-16 15:14:37