C Program exits before taking input from user

Question

Why does my program close before taking the input for k and then displaying it.

I am writing a code for a menu based program so I need to take input from user after he has entered the information so I can have 1.Print names 2.Exit while doing this I realized my program didn't take the input and just skipped the part where it is supposed to take value of l from user. So trying to debug it I deleted stuff and came down to this simple program and realized it still wont work any idea why?

#include <stdio.h>

struct student
{
    char name[50];
    char lname[50];
    float marks;
} s[15];

int main ()
{
    int i, j,k;

    printf("Please enter the number of students:\n");
    scanf ("%d", &j);

    printf ("Please enter the information for students as asked.\n");

    for (i = 0; i < j; i++)
    {
        scanf ("%s %s %f\n", s[i].name, s[i].lname, &s[i].marks);
    }

    printf("Please enter a number\n");
    scanf ("%d", &k);

    printf("your number was %d", k);

    return 0; 
}

When debugging, did you use a debugger? With a debugger you can step through your code line by line to see what happens. I also recommend you take some time to read How to debug small programs by Eric Lippert. — Some programmer dude
– Some programmer dude, Commented Oct 26, 2017 at 3:24
I didnt use any debugger I was trying to debug it based on what I know I dont know what debuggers are Ill try to see if I can use one for this program. — Tyrion
– Tyrion, Commented Oct 26, 2017 at 3:26
You need to learn how to use a debugger, it's one of the most important tools for a programmer. — Barmar
– Barmar, Commented Oct 26, 2017 at 4:00

qwn · Accepted Answer · 2017-10-26 06:58:59Z

1

scanf ("%s %s %f\n", s[i].name, s[i].lname, &s[i].marks);

should be

scanf ("%s %s %f", s[i].name, s[i].lname, &s[i].marks);

The \n in scanf just consumes newline char. It will continue consuming newline until a non-newline char is found, which is put back into stdin for the next IO operation

edited Oct 26, 2017 at 6:58

answered Oct 26, 2017 at 6:50

qwn

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2 Comments

chris Over a year ago

I think maybe this is not the key to his question. Maybe he input char instead of float at the end.

Tyrion Over a year ago

You are right the new line wasnt needed however it still didnt solve my problem but I found an answer you can refer to the thread it looks like my struct definition wasnt as needed.

Angel · Accepted Answer · 2017-10-27 04:28:13Z

0

Try this Code

#include<stdio.h>
typedef struct student
{
char name[50];
char lname[50];
int mark;
}S;

int main ()
{
int i, j,k;

printf("Please enter the number of students:\n");
scanf ("%d", &j);

S record[j];

for (i = 0; i < j; i++)    {
   printf ("Please enter the information for %d student as asked.\n",i+1);

  scanf ("%s %s %f",record[i].name, record[i].lname, &record[i].mark);
}

printf("Please enter a number\n");
scanf ("%d", &k);

printf("your number was %d \n", k);

return 0;
}

You were declaring structure student array in the structure declaration itself.you have to declare the array in main function.

edited Oct 27, 2017 at 4:28

answered Oct 26, 2017 at 9:03

Angel

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2 Comments

Tyrion Over a year ago

This worked can you explain on how that "S" works which we defined just after the structure ended I realize we defined the array once in the main program but what is "S" in S record[j]; Anyways thanks for your help!

Angel Over a year ago

See the Keyword "typedef". you can Give another name to your structure student using this keyword. S is the typedef name of structure Student. reefer this link - fresh2refresh.com/c-programming/c-typedef

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