invalid pointer addintion

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i want to print result of a student .
i m using structure for it.. all the variables are defined in structure while i adding marks of 5 subject then it gives me error like invalid pointer addtion, rather i'd usd more than one structure varibale.

my code is

C#

struct result
{
 char enroll[100];


 int  m1[20],m2[20],m3[20],m4[20],m5[20];

 int t[100];

 int per[100];

};
void result()
{
    struct result r,r1,r2,r3,r4,r5;
    struct record s;

    FILE *fp;

    clrscr();

    fp=fopen("stud.txt","wb");

    printf("Enter Enrollment No : ");

    gets(r.enroll);

    if(strcmp(r.enroll,s.enroll_no)==0)
    {
       printf("Enter Marks for 5 subject:");

       scanf("%d %d %d %d %d",r1.m1,r2.m2,r3.m3,r4.m4,r5.m5);

       r.t=r1.m1+r1.m2+r1.m3+r1.m4+r1.m5;

       r1.per=r.t/5;
    }

    else
    {
    printf("Record Does Not Exist :");

    printf("Press Any Key to Exit ");

    exit(0);
   }

printf("per=%d",r1.per);
printf("total=%d",r.t);
getch();



}

Posted 1-Jan-14 6:37am

Member 10011989

Updated 1-Jan-14 23:47pm

v4

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Comments

fre_ber 1-Jan-14 12:57pm

How is your struct defined? You need to give scanf pointers to the char buffers.

Also, you can't simply add strings in C. Is it string concatenation wou want or adding integers?

Richard MacCutchan 2-Jan-14 6:13am

I think you need to go back to your Student notes or C-language reference and study the language a bit more. There is no point in all these structures and arrays in the above code; in fact in its current state it won't compile.

2 solutions

Solution 1

you are adding strings that wont work. You better use strcat for combine the strings.

but most strange is:

scanf("%s %s %s %s %s",r1.m1,r2.m2,r3.m3,r4.m4,r5.m5);

For eacht string a own member of a different struct?

Why not:

scanf("%s %s %s %s %s",r1.m1,r1.m2,r.m3,r1.m4,r1.m5);

and you better use more describale names than m1. Like name or description...

Posted 1-Jan-14 8:30am

KarstenK

Comments

Member 10011989 2-Jan-14 5:43am

if i used single member of struct the error is same.. after making varibale integer then also i m unable to solve the problem

KarstenK 6-Jan-14 2:24am

CPallini has a fine solution. I didnt get that you wanted to sum up the input :-O

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CPallini · Accepted Answer · 2014-01-02T00:07:00

You should't use strings for storing integers.
And you should always check the return value of scanf. e.g.

C

#include <stdio.h>
#define N 5

struct result
{
  int enroll;
  int m[N];
  int t;

  double per;
};

int main()
{

  struct result r;

  printf("Enter Marks for 5 subjects: ");

  if ( scanf("%d %d %d %d %d",&r.m[0],&r.m[1],&r.m[2],&r.m[3],&r.m[4]) == N)
  {
    int n;
    r.t = 0;
    for ( n=0; n<N; ++n)
      r.t += r.m[n];
    r.per = (double)r.t / N;
    printf("r.t = %d, r.per = %g\n", r.t, r.per);

  }
  else
  {// handle user input error
  }
  return 0;
}