Unable to get output..........

This is a discussion on Unable to get output.......... within the C Programming forums, part of the General Programming Boards category; Code to accept the information of 5 students and display the information of first 3 students...... Code: #include<stdio.h> main() { ...

  1. #1
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    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();
    }
    C enlightened

  2. #2
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    Quote Originally Posted by sameertelkar View Post
    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();
    }
    %c is for char you are scanning an array/string so use %s same for printf plus there is no need for three % symbol in scanf and printf.

  3. #3
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    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.
    Right 98% of the time, and don't care about the other 3%.

  4. #4
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    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.
    C enlightened

  5. #5
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    Quote Originally Posted by sameertelkar View Post
    @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.
    Right 98% of the time, and don't care about the other 3%.

  6. #6
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    ^^^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);
     }
    }
    Last edited by sameertelkar; 08-15-2013 at 08:20 AM.
    C enlightened

  7. #7
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    Quote Originally Posted by sameertelkar View Post
    ^^^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.
    Last edited by Amitesh93; 08-15-2013 at 08:27 AM.

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