1073 Scientific Notation (20 point(s))
题解
转化为字符串处理。
substr有2种用法:
假设:string s = "0123456789";string sub1 = s.substr(5); //只有一个数字5表示从下标为5开始一直到结尾:sub1 = "56789"
string sub2 = s.substr(5, 3); //从下标为5开始截取长度为3位:sub2 = "567"
#include<iostream>
#include<cstdio>
#include<string>
#include<algorithm>
using namespace std;
int main() {
string t, a, n;
cin >> t;
int i = 0;
while(t[i] != 'E') ++i;
if(t[0] == '-') printf("-");
a = t.substr(1, i - 1);
n = t.substr(i + 1);
int b = stoi(n);
if(b < 0) {
cout << "0.";
for(int i = 0; i < - b - 1; ++i) cout << "0";
for(int i = 0; i < a.length(); ++i) if(a[i] != '.') cout << a[i];
} else {
b += 1; // 把个位数加进去。。
int i, j;
for(i = 0, j = 1; i < a.length() && j <= b; ++i) {
if(a[i] == '.') continue;
++j;
cout << a[i];
}
if(j <= b) for(; j <= b; ++j) cout << '0';
if(i < a.length()) printf("."); // 小数时
for(; i < a.length(); ++i) cout << a[i];
}
return 0;
}