在结构指针方面需要帮助

Question

In c++ I have to make a program where I have to write a menu driven program to input, edit or display the name, id and cgpa of a student. The code is as follows:

#include<iostream>
#include<stdlib.h>
#include<stdio.h>
using namespace std;

struct student
{
    char name[20];
    int id;
    float cgpa;
};

void input(struct student *);
void display(struct student *);
void edit(struct student *);

int main()
{
    int ch;
    struct student a;

    while(ch!=4)
    {
        cout<<"1.input";
        cout<<"\n2.edit";
        cout<<"\n3.display";
        cout<<"\n4.exit";
        cout<<"\nenter your choice";
        cin>>ch;
        if(ch==1)
        {
            cout<<"enter name, id and cgpa of student\n";
            input(&a);
        }
        else if(ch==2)
        {
            cout<<"enter new name, id and cgpa  of the student\n";
            edit(&a);
        }
        else if(ch==3)
        {
            display(&a);
        }
        else if(ch==4)
        {
            ch=ch;
        }
        else{cout<<"wrong choice\n";}
    }

    return 0;
}

void input(struct student *s)
{
    cin>>s->name;
    cin.ignore(256,'\n');
    cin>>s->id;
    cin>>s->cgpa;
}

void edit(struct student *s)
{
    cin>>s->name;
    cin.ignore(256,'\n');
    cin>>s->id;
    cin>>s->cgpa;
}

void display(struct student *s)
{
    cout<<s->name<<"\n";
    cout<<s->id<<"\n";
    cout<<s->cgpa<<"\n";
}

But whenever I am inputting a name through cin.getline() function, it doesn't display a name on the screen. Instead a blank space is left there and id and cgpa are printed. Cin is working fine but cin does not take a space. What is wrong in the code that it is not printing the name while using cin.getline().

Answer 1

Call cin.ignore() before calling cin.getline()

Or

make a dummy call cin.getline() to consume the trailing newline character from the cin