Thread: im a newbie at c please help.

  1. #1
    Registered User
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    Sep 2018
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    im a newbie at c please help.

    Please could someone explain to me why this isnt working, also is there a way for me to not have to type in all the variables when i want multiple typed like i have done here. thanks.

    Code:
    #include <stdio.h>
    #include <stdlib.h>
    int main(){
     
     int grade[10][0];
     
     grade[0][0]=0;
     grade[1][0]=0;
     grade[2][0]=0;
     grade[3][0]=0;
     grade[4][0]=0;
     grade[5][0]=0;
     grade[6][0]=0;
     grade[7][0]=0;
     grade[8][0]=0;
     grade[9][0]=0;
     printf("Please enter your students exam mark seperated by a space \n");
     fflush(stdin);
     scanf("%d %d %d %d %d %d %d %d %d %d \n", grade[1][0], grade[2][0], grade[3][0],grade[4][0], grade[5][0], grade[6][0], grade[7][0], grade[8][0], grade[9][0], grade[0][0]);
     float totgrade= grade[1][0]+grade[2][0]+grade[3][0]+grade[4][0]+grade[5][0]+grade[6][0]+grade[7][0]+grade[8][0]+grade[9][0]+grade[10][0];
     
     printf("The total mark is: %f \n", totgrade);
     
     float avgrade=totgrade/10;
     printf("The average mark = %.1f", avgrade);
     
     system("pause");
     return 0; 
    }

  2. #2
    C++ Witch laserlight's Avatar
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    This doesn't make sense and should have resulted in a compile error, or at least a warning:
    Code:
    int grade[10][0];
    It looks like you want to read in the grades of ten students, one grade per student, so you should have written:
    Code:
    int grade[10] = {0};
    The zero initialisation means that you don't have to manually set the initial value of all the elements to zero.

    This is non-standard and you should remove it since you don't need it here:
    Code:
    fflush(stdin);
    Next, for the scanf, while you could have a format string consisting of ten format specifiers, you may find it easier to use a loop that reads one grade per iteration. Note that the elements of the grade array start from grade[0] and ends at grade[9], not grade[10].

    Oh, and remember to indent your code so as to make it more readable.
    Quote Originally Posted by Bjarne Stroustrup (2000-10-14)
    I get maybe two dozen requests for help with some sort of programming or design problem every day. Most have more sense than to send me hundreds of lines of code. If they do, I ask them to find the smallest example that exhibits the problem and send me that. Mostly, they then find the error themselves. "Finding the smallest program that demonstrates the error" is a powerful debugging tool.
    Look up a C++ Reference and learn How To Ask Questions The Smart Way

  3. #3
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    Sep 2018
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    Ive got to this but it still crashes after i input the 10 numbers.

    Code:
    #include <stdio.h>
    #include <stdlib.h>
    int main(){
     
     int grade[10]={0};
      printf("Please enter your students exam mark seperated by a space \n");
      scanf("%d %d %d %d %d %d %d %d %d %d \n", grade[1], grade[2], grade[3],grade[4], grade[5], grade[6], grade[7], grade[8], grade[9], grade[0]);
      printf("%d", grade[4]);
     
     float totgrade= grade[1]+grade[2]+grade[3]+grade[4]+grade[5]+grade[6]+grade[7]+grade[8]+grade[9]+grade[0];
     
      printf("The total mark is: %f \n", totgrade);
     
     float avgrade=totgrade/10;
      printf("The average mark = %.1f", avgrade);
     
     system("pause");
     return 0; 
    }

  4. #4
    and the hat of int overfl Salem's Avatar
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    Every grade in your scanf line needs to be &grade[n]

    A better compiler will tell you such things.
    Code:
    $ gcc -Wall foo.c
    foo.c: In function ‘main’:
    foo.c:7:9: warning: format ‘%d’ expects argument of type ‘int *’, but argument 2 has type ‘int’ [-Wformat=]
       scanf("%d %d %d %d %d %d %d %d %d %d \n", grade[1], grade[2], grade[3],grade[4], grade[5], grade[6], grade[7], grade[8], grade[9], grade[0]);
             ^
    foo.c:7:9: warning: format ‘%d’ expects argument of type ‘int *’, but argument 3 has type ‘int’ [-Wformat=]
    foo.c:7:9: warning: format ‘%d’ expects argument of type ‘int *’, but argument 4 has type ‘int’ [-Wformat=]
    foo.c:7:9: warning: format ‘%d’ expects argument of type ‘int *’, but argument 5 has type ‘int’ [-Wformat=]
    foo.c:7:9: warning: format ‘%d’ expects argument of type ‘int *’, but argument 6 has type ‘int’ [-Wformat=]
    foo.c:7:9: warning: format ‘%d’ expects argument of type ‘int *’, but argument 7 has type ‘int’ [-Wformat=]
    foo.c:7:9: warning: format ‘%d’ expects argument of type ‘int *’, but argument 8 has type ‘int’ [-Wformat=]
    foo.c:7:9: warning: format ‘%d’ expects argument of type ‘int *’, but argument 9 has type ‘int’ [-Wformat=]
    foo.c:7:9: warning: format ‘%d’ expects argument of type ‘int *’, but argument 10 has type ‘int’ [-Wformat=]
    foo.c:7:9: warning: format ‘%d’ expects argument of type ‘int *’, but argument 11 has type ‘int’ [-Wformat=]
    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.

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