How can I input and store information in functions and structure?

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I have an assignment and I'm still a beginner.
I have a problem on being able to input a single student data and displaying it using only functions (function calls, prototype and definitions) in the main function.
I tried doing it but what goes on to the screen during execution has a word null in where the word is supposed to be.
Please help.

What I have tried:

Doing the functions and even foregoing the functions and doing everything in the main function but still there is a null during execution.

C

/* The program will have 2 versions of the function used to   *
 * input student records: getStudentV1() and getStudentV2().  *
 *                                                            * 
 * Function displayStud() will display information of 1       *
 * student record in 1 horizontal line.                       *
 * Function displayHeader() is called before displayStud() is *
 * called.                                                    *
 **************************************************************/

#include <stdio.h>
#include <string.h>

typedef struct {
	char fname[24];     /* firstname */
	char lname[16];     /* lastname  */ 
	char mi;            /* middle initial */ 
}nametype;

typedef struct {
	nametype name;
	unsigned int ID;
	char course[8];
	int yrLevel;
}studtype;

studtype getStudentV1();        
void getStudentV2(studtype *S); 
void displayHeader();          
void displayStud(studtype S);     

int main()
{

  getStudentV1();
  displayHeader();
  displayStud(student);

  return 0;
}


void displayHeader()
{
  printf("\n%-10s", "ID");   
}

void getStudentV1(){
  printf("Enter student ID Number: \n);
  scanf("%d", &student.ID);

void displayStud(studtype S){
	
  studtype student;
  printf("\n%-10s", student.ID);
}

Posted 6-May-20 4:17am

Jill Pine

Updated 6-May-20 7:36am

phil.o

v3

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phil.o 6-May-20 10:20am

Please use the green "Improve question" widget and qualify the "What I have tried" section with the code causing the problem.

phil.o 6-May-20 10:45am

Some part of the code appears to be missing from your sample (in the getStudentV1() function. Could you correct that please? And there is a double-quote missing at the end of the string in the printf() function in it.

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Richard MacCutchan · Answer 1 · 2020-05-06T05:32:00

C++

void getStudentV1(){
  printf("Enter student ID Number: \n);
  scanf("%d", &student.ID); // you refer to student.ID but there is no variable student declared anywhere.

void displayStud(studtype S){ // you pass in a structure named S but never refer to it
	
  studtype student; // you are creating a local student structure which will disappear when this function returns.
  printf("\n%-10s", student.ID); // the local student structure does not contain any information
}

You should create your structure variables in main and pass pointers to them to your functions; something like:

C++

int main()
{
    studtype student;

    getStudentV1(&student);
    displayHeader(&student);
    displayStud(&student);

  return 0;
}

void getStudentV1(studtype *student)
{
    // you can now refer to the individual fields
    // using 'arrow' notation thus:
    scanf("%d", &student->ID);

    // use similar references to collect the other details
    // but you will need to use both 'arrow' and 'dot' when
    // collecting the name fields:
   //        student->name.fname
}

KarstenK · Answer 2 · 2020-05-06T07:37:00

Solution 1 is correct, but when you want to store more information you need to allocate some memory.

C++

 int studentCount = 10;//or ask the user
//allocate memory for the students
studtype *students = new studtype[studentCount];

 //loop and work with students
for( int i = 0; i < studentCount; i++ ){
//use a single student
studtype *student = students[i];
}

delete students; // free the memory

This has the advantage that you can use some students in your code. Visit the Learn C++ tutorial to about the language and its usage.

Learn to use the debugger. Good luck :-)

How can I input and store information in functions and structure?

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