reading 2 ints and a char

This is a discussion on reading 2 ints and a char within the C Programming forums, part of the General Programming Boards category; Hello I want to read 2 integers and 1 character. I have a function named input called from main. The ...

  1. #1
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    reading 2 ints and a char

    Hello
    I want to read 2 integers and 1 character. I have a function named input called from main.
    The code I have is below. But when I check the values read I get different values, i.e

    Enter value 1: 2
    Enter char value 2: M
    Enter value 3: 4
    read values: 2293580 K 2293572

    Code:
    #include <stdio.h>
    #include <string.h>  //not sure needed
    #include <stdlib.h>  // not sure needed
    
    void input(int* val1, char* val2, int* val3);
    
    void main()
    {
        int val1;       // value 1
        char val2;    // value 2
        int val3;          // value 3
    
        input(&val1, &val2, &val3);
    
        printf ("read values: %d %c %d", &val1, &val2, &val3);
    
    }
    
    void input(int* val1, char* val2, int* val3)
    {
        //Input from the user
        printf ("Enter value 1: ");
        scanf ("%d", val1);
        printf ("Enter char value 2: ");
        scanf ("%s", val2);
        printf ("Enter value 3: ");
        scanf ("%d", val3);
    
    }

  2. #2
    and the hat of wrongness Salem's Avatar
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    $ gcc -Wall bar.c
    bar.c:7: warning: return type of ‘main’ is not ‘int’
    bar.c: In function ‘main’:
    bar.c:15: warning: format ‘%d’ expects type ‘int’, but argument 2 has type ‘int *’
    bar.c:15: warning: format ‘%c’ expects type ‘int’, but argument 3 has type ‘char *’
    bar.c:15: warning: format ‘%d’ expects type ‘int’, but argument 4 has type ‘int *’

    And you're using %s to read into a single char.
    If you dance barefoot on the broken glass of undefined behaviour, you've got to expect the occasional cut.
    If at first you don't succeed, try writing your phone number on the exam paper.
    I support http://www.ukip.org/ as the first necessary step to a free Europe.

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    I'm not returning any values in main. How should the values be sent back from the input function?

    Thanks

  4. #4
    and the hat of wrongness Salem's Avatar
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    > How should the values be sent back from the input function?
    No, that bit of your code is actually OK.
    It's the use of & in your printf which is screwing up.

    And using %s in a scanf where you should have used " %c" instead.
    If you dance barefoot on the broken glass of undefined behaviour, you've got to expect the occasional cut.
    If at first you don't succeed, try writing your phone number on the exam paper.
    I support http://www.ukip.org/ as the first necessary step to a free Europe.

  5. #5
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    I see what you mean. I removed the & signs from the printf statement on line 15. Now the values for the 2nd and 3rd values show correct but not the first one. Output for 1st value shows as 0 for some reason.

    Thank you

  6. #6
    Registered User DevoAjit's Avatar
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    I don't think so that there is need of pointers... remove the pointers and try diffrent variables of 2 ints and 1 char in void main block..

  7. #7
    and the hat of wrongness Salem's Avatar
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    > Output for 1st value shows as 0 for some reason.
    And did you change
    scanf ("%s", val2);
    to
    scanf (" %c", val2);

    If you read a string, you're going to be trashing memory - like your int variables.
    If you dance barefoot on the broken glass of undefined behaviour, you've got to expect the occasional cut.
    If at first you don't succeed, try writing your phone number on the exam paper.
    I support http://www.ukip.org/ as the first necessary step to a free Europe.

  8. #8
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    Quote Originally Posted by Salem View Post
    > Output for 1st value shows as 0 for some reason.
    And did you change
    scanf ("%s", val2);
    to
    scanf (" %c", val2);

    If you read a string, you're going to be trashing memory - like your int variables.
    Salem
    As soon as I replace the %s with a %c, the program does not accept a value for the second value. The output I get is:

    Enter value 1: 7
    Enter char value 2: Enter value 3: 5
    read values: 7
    5


    Thanks

  9. #9
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    Quote Originally Posted by DevoAjit View Post
    I don't think so that there is need of pointers... remove the pointers and try diffrent variables of 2 ints and 1 char in void main block..
    If I remove the pointers, it seems to hang after I input the value 1. Thanks

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    Quote Originally Posted by wearld97 View Post
    Salem
    As soon as I replace the %s with a %c, the program does not accept a value for the second value. The output I get is:

    Enter value 1: 7
    Enter char value 2: Enter value 3: 5
    read values: 7
    5


    Thanks
    Shouldn't the second variable be a character instead of a number?

  11. #11
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    Quote Originally Posted by 7h3_0r4c1_3 View Post
    Shouldn't the second variable be a character instead of a number?
    Correct, but it doesn't wait to allow typing the 2nd value. Instead after displaying the line "Enter char value 2:"
    For some reason it it immediately displays the line "Enter value 3:" on the same line.

  12. #12
    and the hat of wrongness Salem's Avatar
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    Did you specifically note the extra SPACE before the %c ?

    Yes, it really matters!
    If you dance barefoot on the broken glass of undefined behaviour, you've got to expect the occasional cut.
    If at first you don't succeed, try writing your phone number on the exam paper.
    I support http://www.ukip.org/ as the first necessary step to a free Europe.

  13. #13
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    Salem,
    Do you mean to check on the space on line 25 before the %c? If yes, I did but it didn't help. Thanks.

  14. #14
    and the hat of wrongness Salem's Avatar
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    Post your latest code then please.
    If you dance barefoot on the broken glass of undefined behaviour, you've got to expect the occasional cut.
    If at first you don't succeed, try writing your phone number on the exam paper.
    I support http://www.ukip.org/ as the first necessary step to a free Europe.

  15. #15
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    Quote Originally Posted by Salem View Post
    Post your latest code then please.
    Here it is...Thanks

    Code:
    #include <stdio.h>
    #include <string.h>  //not sure needed
    #include <stdlib.h>  // not sure needed
    
    void input(int* val1, char* val2, int* val3);
    
    void main()
    {
        int val1;       // value 1
        char val2;    // value 2
        int val3;          // value 3
    
        input(&val1, &val2, &val3);
    
        printf ("read values: %d %c %d", val1, val2, val3);
    
    }
    
    void input(int* val1, char* val2, int* val3)
    {
        //Input from the user
        printf ("Enter value 1: ");
        scanf ("%d", val1);
        printf ("Enter char value 2: ");
        scanf ("%c", val2);
        printf ("Enter value 3: ");
        scanf ("%d", val3);
    
    }

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