参考算法笔记

输入样例

+1.23400E-03

输出样例

0.00123400

C++代码

#include <iostream>
#include <cmath>
#include <cstdio>
#include <cstring>
#include <cstdlib>
#include <algorithm>
#include <vector>
#include <queue>
#include <unordered_map>
#include <unordered_set>
using namespace std;
typedef pair<int, int> PII;
typedef long long LL;
const int N = 10010;
char s[N];
int main( ) {
    scanf("%s", s);
    int len = strlen(s);
    if ( s[0] == '-' ) cout << "-";

    int pos = 0;
    while ( s[pos] != 'E' ) pos++;

    int exp = 0;
    for ( int i = pos+2; i < len; i++ ) {
        exp = exp * 10 + ( s[i] - '0' );
    }

    if ( exp ==  0 ) {
        for ( int i =1; i < pos; i++ ) {
            cout << s[i];
        }
    }

    if ( s[pos+1] == '-' ) {
        cout << "0.";
        for ( int i=0; i < exp - 1; i++ ) {
            cout << 0;
        }
        cout << s[1];
        for ( int i = 3; i < pos; i++ ) {
            cout << s[i];
        }
    }
    else {
        for ( int i=1; i < pos; i++ ) {
            if ( s[i] == '.' ) continue;
            cout << s[i];
            if ( i == exp + 2 && pos - 3 != exp ) {
                cout << ".";
            }
        }
        for ( int i=0; i < exp - ( pos - 3); i++ ) {
            cout << 0;
        }
    }
    return 0;
}