'How to copy char array of a structure into another char array of a structure?

#include <iostream>
using namespace std;

struct stud
{
    char name[10];
    int id;
};

int input(stud a[], int size)
{
    for(int i=1; i<=size; i++)
    {
        cout<<"name = ";
        cin>>a[i].name;
        cout<<"id = ";
        cin>>a[i].id;
    }
    cout<<endl;
    return 0;
}
int output(stud a[], int size)
{
    for(int i=1; i<=size; i++)
    {
        cout<<"name = "<<a[i].name<<" ";
        cout<<"id = "<<a[i].id<<" ";
    }
    cout<<endl;
    return 0;
}

int copy(stud a[], stud x[], int size)
{

    for(int i=1; i<=size; i++)
    {
        x[i].name=a[i].name; 
        x[i].id=a[i].id;
    }
    output(x,size);
    cout<<endl;
    return 0;
}

int main()
{

    struct stud s[3], x[3];
    input(s,3);
    output(s,3);
    copy(s,x,3);
    return 0;
}

In this program the statement in function copy x[i].name =a[i].name; is not copying contents from 1 structure object to another. I have tried to put this statement in for loop for(int j=1;j<=10;j++) x[i].name[j] =a[i].name[j]; but still not working. please suggest what should be changed or some alternatives for this. i'll be very thankful to you for this.

regards, umar

c++arraysstructure


Solution 1:[1]

Either using a loop to copy each character in the name field or using thestrcpy function from <cstring> header works.

int copy(stud a[], stud x[], int size) {
    for(int i = 1; i <= size; i++) {
        // for(unsigned j = 0; j < 10; j++) {
        //     x[i].name[j] = a[i].name[j];
        // }
        strcpy(x[i].name, a[i].name);
        x[i].id = a[i].id;
    }
    output(x, size);
    cout << endl;
    return 0;
}

But since you tagged this as c++, consider using std::string instead of a char array, unless you have a particular reason for using a char array. In that case x[i].name = a[i].name would have worked just fine and you could also use the standard algorithm library for copy. Also, using std::array instead of a raw C array for you "array of structures" might be a better option (does not degenerate into a pointer like a regular C array does).

Solution 2:[2]

Evrey single one of your loops is wrong, because in C++ arrays start at zero. So not

for(int i=1; i<=size; i++)

instead

for(int i=0; i<size; i++)

You cannot copy arrays by writing a = b;. Since your arrays are really strings there's a built in function strcpy to copy strings.

strcpy(x[i].name, a[i].name);

Solution 3:[3]

If you use = to copy struct, the char array inside that struct will be copied. You don't need to do anything more.

#include <iostream>

using namespace std;
typedef struct{
    char name[10];
} type_t;

int main() {
    type_t a = {"hihi"};
    
    type_t b;
    b = a;
    
    a.name[0] = 'a';
    
    cout<<a.name<<endl;
    cout<<b.name<<endl;
    

    return 0;
}

output: aihi hihi

ideone: https://ideone.com/Zk5YFd

Sources

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Source: Stack Overflow

Solution Source
Solution 1
Solution 2 john
Solution 3 chouhy

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