PAT basic 1024

#include <iostream>#include <string>using namespace std;int main() {    string s;    cin >> s;    int len = s.length();    if (s[0] == '-')        cout << "-";    int pose = 0;    for (int i = 1; i < len; i++) {        //找到E的位置         if (s[i] == 'E')            pose = i;    }    int after = 0;    for (int i = pose + 2; i < len; i++) {     //E之后的数字 ，不包括符号         after = (s[i] - '0') + 10 * after;    }    if (s[pose + 1] == '-') {        if (0 < after) {                cout << "0.";            for (int i = 1; i < after; i++) {                cout << 0;            }            for (int i = 1; i < pose; i++) {                if (s[i] >= '0' && s[i] <= '9') {                    cout << s[i];                }            }        } else {            for (int i = 1; i < pose; i++) {                if (i == 2 - after) {                    cout << ".";                }                if (s[i] >= '0' && s[i] <= '9') {                    cout << s[i];                }            }        }    }    else {        if (pose - 3 < after) {            if (s[1] != '0')                cout << s[1];            for (int i = 3; i < pose; i++) {                if (s[i] >= '0' && s[i] <= '9') {                    cout << s[i];                }            }            for (int i = 0; i < after - (pose - 3); i++) {                cout << 0;            }        }        else {            if (s[1] != '0')                cout << s[1];            for (int i = 3; i < pose; i++) {                if (i == 3 + after) {                    cout << ".";                }                if (s[i] >= '0' && s[i] <= '9') {                    cout << s[i];                }            }        }    }    return 0;}