题解 | #10进制 VS 2进制#

//一个int型数a（建设为5），a+'0'为53,所以此时若想表示‘5’，则应用char强制类型转换，若用to_string则为”53“
#include "stdio.h"
#include "string"
#include "algorithm"
using namespace std;
string change(int init,int ter,string numStr){//init为原先的进制，ter为转换后的进制
    string str="";//记录转换进制后的字符串     //num[]为要转换的字符换
    int len = numStr.size();
    for (int i = 0; i < len; ) {
        int remainder = 0;//每次除法时，余数肯定默认是0
        for (int j = i; j < len; ++j) {//j从i开始是为了抹掉开始的0
            int k = (remainder*init + numStr[j]-'0')%ter;
            numStr[j] = (remainder*init + numStr[j]-'0')/ter + '0';
            remainder = k;
        }
        str = str+char (remainder+'0');
        while (numStr[i]=='0')
            ++i;
    }
    return str;
}

int main(){
    char inPUT[1010];
    while (scanf("%s",inPUT)!=EOF){
        string binary = change(10,2,inPUT);
        string decimal = change(2,10,binary);
        reverse(decimal.begin(),decimal.end());
        printf("%s",decimal.c_str());
    }
}