Thread: Unable to get output..........

Code to accept the information of 5 students and display the information of first 3 students......

Code:

#include<stdio.h>
main()
{
 struct stud
 {
  char name[20];
  int rollno;
  float per;
  char grade;
 };
 struct stud s[5];
 int i;
 printf("enter the information of 5 students\n");
 for(i=0;i<=4;i++)
 {
  scanf("%c%d%",&s[i].name,&s[i].rollno);
  scanf("%f%c%",&s[i].per,&s[i].grade);
 }
 printf("the information of first three students is\n");
 for(i=0;i<=2;i++)
 {
  printf("%c%d%\n",s[i].name,s[i].rollno);
  printf("%f%c%",s[i].per,s[i].grade);
 }
 getch();
}

Your code has quite a few problems, given that it is a fairly small sample. And you've only asked about the FIRST!

1) Use the %s format to read and write strings (arrays of characters, such as you might expect in the name of a student), not %c.

2) When passing &s[i].name to scanf, lose the ampersand (not required for arrays, and changes the meaning of the code as well).

3) When looping over an array of 5 elements, valid indices are 0 to 4, not 0 to 5. So don't loop while i <= 4 in the first loop.

4) In each of the format strings, the last % sign is misplaced. Remove it.

5) Be aware that the scanf() %s format stops when it encounters whitespace. If you enter Peter Jones 2, the %s will only pick up Peter, not Jones.

6) Check the return values from scanf() to see how many arguments it has successfully read.

7) Main returns int, so type that explicitly. Beginners, and a few too many teachers, think it is smart to leave the "int" off. They are wrong.

7) Don't mix formatted I/O (like scanf() calls) with character oriented I/O (like getch()). scanf() often stops when it encounters whitespace, but leaves that whitespace character waiting to be read. getch() will then encounter than whitespace, and return it without pausing.

oops,I was careless to add that meaningless % over there
@Amitesh,I changed the scanf of name to %s but still ain't getting output
@grumpy,can you please correct the code?I am a beginner to C and cannot comprehend the nomenclature.Thanks.

Originally Posted by sameertelkar

@grumpy,can you please correct the code?I am a beginner to C and cannot comprehend the nomenclature.Thanks.

I can, obviously, or I couldn't have spotted the problems. But you will learn more by trying to fix each concern yourself. Work through the concerns, one at a time. If you don't understand the nomenclature, feel free to ask - if it is obvious you are applying a genuine effort, you might even get an answer.

^^^What is the meaning of typing main explicitly?Does it mean int main()?Also I omitted the ampersand and getch sign as you said,here is the updated code,I have shortened it to 3 students.......

Code:

#include<stdio.h>
int main()
{
 struct stud
 {
  char name[20];
  int rollno;
  float per;
  char grade;
 };
 struct stud s[3];
 int i;
 printf("enter the information of 3 students\n");
 for(i=0;i<=2;i++)
 {
  scanf("%s%d",s[i].name,&s[i].rollno);
  scanf("%f%c",&s[i].per,&s[i].grade);
 }
 printf("the information of three students is\n");
 for(i=0;i<=2;i++)
 {
  printf("%s%d\n",s[i].name,s[i].rollno);
  printf("%f%c",s[i].per,s[i].grade);
 }
}

Originally Posted by sameertelkar

^^^What is the meaning of typing main explicitly?Does it mean int main()?

writting explicitly means to write it fully in the code and it not being an implicit declaration.

Code:

for(i=0;i<=4;i++) {
  scanf("%c%d%",&s[i].name,&s[i].rollno);

  scanf("%f%c%",&s[i].per,&s[i].grade);
 }

your error is basically in the scanning first of try to write code with more clarity ,like say

Code:

for(i=0;i<5;i++) {

  printf("Enter name\n");
  scanf("%s",s[i].name);
  printf("Enter roll no\n");
  scanf("%d",&s[i].rollno);
 }

by this you can check wether each step is processing properly or not.