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Scientific Notation

题目链接：1073 Scientific Notation (20 point(s))

题干大意

将科学计数法的数字表示成正常的形式

思路

限定为E的位置，然后根据指数正负分情况，总结规律

AC代码

C++
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#include <iostream>
#include <string>
#include <vector>
using namespace std;

int main()
{
    string str;
    cin >> str;
    if (str[0] == '-')
        cout << '-';
    int pos = 0;
    while (str[pos] != 'E')
        ++pos;
    int exp = 0; // 计算指数
    for (int i = pos + 2; i < str.length(); ++i) {
        exp = exp * 10 + (str[i] - '0');
    }
    if (exp == 0) {
        for (int i = 1; i < pos; ++i)
            cout << str[i];
    }
    if (str[pos + 1] == '-') {
        cout << "0.";
        for (int i = 0; i < exp - 1; ++i)
            cout << 0;
        cout << str[1];
        for (int i = 3; i < pos; ++i)
            cout << str[i];
    } else {
        for (int i = 1; i < pos; ++i) {
            if (str[i] == '.')
                continue;
            cout << str[i];
            if (i == exp + 2 && pos - 3 != exp) // 3为原小数点位置
                cout << ".";
        }
        for (int i = 0; i < exp - (pos - 3); ++i)
            cout << 0;
    }
    return 0;
}