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  • c++数字和字符串的转换

    1  利用stringstream

       添加头文件 #include<sstream>

       数字转字符串

       #include <string>

      #include <sstream>

      int main(){
        double a = 123.32;
        string res;
        stringstream ss;          定义流ss
        ss << a;                       将数字a转化成流ss
        ss >> res;                    将流ss转化成字符串
        return 0;
      }

       字符串转数字

      #include <string>

      #include <sstream>

      int main(){
        double a ;
        string res= "123.32";
        stringstream ss;  
        ss << res;                  
        ss >> a;
        return 0;
      }

    //此处包装了一个方法,将一位的数字转化成两位的字符串

    //0->"00"    1->''01"

    string transform(int num)
    {
     string res;
     stringstream ss;
     ss<<num;
     ss>>res;
     if(num<10)
     {
      res="0"+res;
     }
     return res;
    }

    2.利用 sprintf()函数和sscanf()函数

    sprintf() 用于将数字转化为字符串

    #include <iostream>
    #include <string>
    using namespace std;

    int main()
    {
        char str[10];
        int a=1234321;
        //将整数转化为字符串
        sprintf(str,"%d",a);
        int len=strlen(str);
        cout<<"字符串"<<str<<endl;
        cout<<"长度"<<len<<endl;

        char str1[10];
        double b=123.321;
        / /将浮点数转化为字符串
        sprintf(str1,"%.3lf",b);
        int len1=strlen(str1);
        cout<<"字符串"<<str1<<endl;
        cout<<"长度"<<len1<<endl;
        return 0;
    }

    sscanf() 用于将字符串转化为数字

    #include <iostream>
    #include <string>
    using namespace std;

    int main()
    {
        char str[]="1234321";
        int a;
        sscanf(str,"%d",&a);
        cout<<a<<endl;

        char str1[]="123.321";
        double b;
        sscanf(str1,"%lf",&b);
        cout<<b<<endl;
        return 0;
    }

     

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  • 原文地址:https://www.cnblogs.com/houchen/p/8984164.html
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