C ++处理“结构”和字符串

Question

I have A problem in my C++ Code , I want to add 'n' number of Students with there Each Date , but I have an error when I Compare with if , here is my code

#include <iostream>
#include <stdio.h>
#include <string.h>
struct Address
{
char city[20];
char street[20];    
};
struct University
{
char name1[20],name2[20],name3[20]; 
};
struct student 
{   
char name[20];
char degree[20];
University un;
Address add;
};

using namespace std;
int main (){

    student st[20];
    int n,i,j;
    do{cin>>n;}while(n<=0 || n>20);

    for(i=0;i<n;i++)
    {
        cout<<" Name Of student  "<<i+1<<"\n";
        cin>>st[i].name;

        cout<<" Degree Of student  "<<i+1<<"\n";
        cin>>st[i].degree;

        cout<<"   University 1 \n";
        cin>>st[i].un.name1;
        cout<<"   University 2 \n";
        cin>>st[i].un.name2;
        cout<<"   University 3 \n";
        cin>>st[i].un.name3;

        cout<<" Enter The City Of student  "<<i+1<<"\n";
        cin>>st[i].add.city;

        cout<<" Enter The Street Of student  "<<i+1<<"\n";
        cin>>st[i].add.street;

        cout<<"\n* * * * * * * * * * * * * * * * * * * *\n";

    }   

    for(i=0;i<n;i++)
        if(st[i].degree == "phD")
        cout<<st[i].name<<"  is  OK";

    cout<<endl;
    return 0;
}

So , I want To Check if the Student Has "phD" Then Output his name , But I get An Error , there is not output after the Date inputed , Why ? And When I change the date type of " degree " to string then I get Another Error in the if Say (is not a member of 'student').But I Really Want to do it With char , Can Help me please ?

Answer 1

For members like char city[20]; , you should instead consider the std::string type. It provides the equality operator that you use in your comparison ( == ) and several other features.

Answer 2

use strcmp ( http://en.cppreference.com/w/c/string/byte/strcmp ) to compare char strings

like:

for(i=0;i<n;i++)
        if(strcmp(st[i].degree,"phD") == 0)
        cout<<st[i].name<<"  is  OK";

or

IF you wanna use string in struct you can change your code like this :

struct student 
{   
char name[20];
string degree;
University un;
Address add;
};

then your for loop will remain same