Not an Expected Result Loop of a Structure in c [closed] - c

Question

Closed. This question is not reproducible or was caused by typos. It is not currently accepting answers.
This question was caused by a typo or a problem that can no longer be reproduced. While similar questions may be on-topic here, this one was resolved in a way less likely to help future readers.
Closed 4 years ago.
Improve this question
I am working on a simple C program which is to create a loop of a structure.
So I have a structure of a Students with name, age, and grade.
So the output will be something like this:
Enter name of student 1:
Enter age of student 1:
Enter Grade of student 1:
Enter name of student 2:
Enter age of student 2:
Enter Grade of student 2:
But after I input the grade of Student 1, it skipped The name of student 2 so I got this instead:
Enter name of student 1:
Enter age of student 1:
Enter Grade of student 1:
Enter name of student 2: Enter age of student 2:
And I am using DevC++, here is my code:
#include <stdio.h>
struct student {
char name[50]; // declare name using array
int age;
int grade;
};
int main ()
{
struct student info[3]; //declare 3 students [3]
int i;
for(i=1;i<=3;i++) { // this is for the looping, student 1, student 2, student 3
printf("Enter name for student %d : ",i);
scanf("%s",info[i].name); // called struct using "." (dot)
printf("Enter age for sudent %d : ",i);
scanf("%d",&info[i].age);
printf("Enter grade for student %d : ",i);
scanf("%d",&info[i].grade);
}
return 0;
}
Can someone find what is wrong with my code? or please help a suggestion to solve this problem to get the expected result.

Answer 1

Multiple suggestions of your code:
When using scanf to input data, always check its return value to make sure sufficient data is input correctly, for example, when you input B for the int grade field, it returns zero instead of one:
int r = scanf("%d", &info[i].grade);
printf("%d\n", r); // 0
Also as said in the comments, when you input strings try use fgets, because it is more secure and will not stop at spaces. scanf does not check for buffer overflow.
Also, in your for loop, you are accessing out of bounds of the array info, you have to start from 0.
Try the following:
int main ()
{
struct student info[3]; //declare 3 students [3]
int i;
int r;
for(i=0; i < 3; i++) {
printf("Enter name for student %d : ",i);
fgets(info[i].name, 50, stdin);
printf("Enter age for sudent %d : ",i);
r = scanf("%d", &info[i].age);
if (r < 1) {
printf("input error, exiting\n");
return 1;
}
printf("Enter grade for student %d : ",i);
r = scanf("%d", &info[i].grade);
if (r < 1) {
printf("input error, retry\n");
return 1;
}
}
return 0;
}

Answer 2

I Tried your code and it work succesfully, I tried to compare it with what you have done.
And The result is you declare scanf("%d",&info[i].grade);
which is received an integer input. but when I see your picture your Input was a Character
So Just Change Your Input with an Integer on Enter grade for student i

Answer 3

To expand on the answer by Serafin: (Good catch, BTW!)
When you input a non-number into your scanf call,
printf("Enter grade for student %d : ",i);
scanf will fail to read the input (see comment by hyde, thanks)
scanf will skip all inputs that don't match the input pattern provided until it hits newline. Anything that was not matched read remains in the input buffer. Therefore, the subsequent call to scanf receives the old content from the previous input, which does get matched in this case.

Answer 4

grade is int but you type a char ('B', It's like 8 :D), I modity three line:
#include <stdio.h>
struct student {
char name[50]; // declare name using array
int age;
char grade; // int -> char
};
int main ()
{
struct student info[3]; //declare 3 students [3]
int i;
for(i=1;i<=3;i++) { // this is for the looping, student 1, student 2, student 3
printf("Enter name for student %d : ",i);
scanf("%s",info[i].name); // called struct using "." (dot)
printf("Enter age for sudent %d : ",i);
scanf("%d",&info[i].age);
getchar(); // reade '\n' after type age
printf("Enter grade for student %d : ",i);
scanf("%c",&info[i].grade); // %d -> %c
}
return 0;
}