mystr.cpp

#include <stdlib.h>
#include "mystr.h"
using namespace std;

int StrToI(const string& s) {
    int m = 0, sign = 0;
    for (int i = 0; i < s.size(); i++) {
        if (s[i] >= '0' && s[i] <= '9') {
            m *= 10;
            m += s[i] - '0';
        }
        else
            sign = 1;
    }
    if (sign)
        return -m;
    return m;
}

const string IToStr(int n, int length) {
    int sign = 0;
    if (n < 0) {
        n = -n;
        sign = 1;
    }
    char *s = (char *)malloc(sizeof(char) * (length + 1));
    s[length] = '\0';
    for (int i = length - 1; i >= 0; i--) {
        if (n == 0 && sign) {
            s[i] = '-';
            sign = 0;
        }
        else
            s[i] = n % 10 + '0';
        n /= 10;
    }
    string ss(s);
    free(s);
    return ss;
}

int FindFirstNon0(const string& s) {
    int i;
    for (i = 0; i < s.size(); i++)
        if (s[i] != '0')
            break;
    return i;
}

int IntCmp(const string& s, const string& t) {
    int i = FindFirstNon0(s);
    int j = FindFirstNon0(t);
    int n = atoi(s.substr(i, s.size() - i).c_str());
    int m = atoi(t.substr(j, t.size() - j).c_str());
    return n - m;
}

int FloatCmp(const string& s, const string& t) {
    int i = FindFirstNon0(s);
    int j = FindFirstNon0(t);
    float n = atof(s.substr(i, s.size() - i).c_str());
    float m = atof(t.substr(j, t.size() - j).c_str());
    if (n < m)
        return -1;
    else if (n > m)
        return 1;
    else
        return 0;
}

int StrCmp(const string& s, const string& t) {
    int i = FindFirstNon0(s);
    int j = FindFirstNon0(t);
    string n = s.substr(i, s.size() - i).c_str();
    string m = t.substr(j, t.size() - j).c_str();
    if (n < m)
        return -1;
    else if (n > m)
        return 1;
    else
        return 0;
}


const std::string SpanStrToLen(std::string s, int length) {
    while (s.size() < length)
        s = "0" + s;
    return s;
}