Thread: Hello! Need a little help with c structures assignment

Code:

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#include<stdio.h>
#include<string.h>
#include<stdlib.h>


struct Student
{
    char fname[20], lname[20], id[10];
    float golch ;
};
typedef struct Student s1 ;
//by the way golch means GPA//




void read_students (s1 a[], int n)
{
    int i;
    for(i=0; i<n; i++)
    {
        scanf("%s %s %s %f",&a[i].fname, &a[i].lname, &a[i].id, &a[i].golch);
    }
}


void print_students (s1 a[], int n)
{
    int i;
    for(i=0; i<n; i++)
    {
        printf("%s %s %s %.1f\n",a[i].fname, a[i].lname, a[i].id, a[i].golch);
    }
}


int search_by_fname (s1 a[], int n, char fname[])
{
    int i;
    for(i=0; i<n; i++)
    {
        if(strcmp(a[i].fname, fname)==0)
        {
            return i;
        }
        else
            return -1;
    }
}


int search_by_lname (s1 a[], int n, char lname[])
{
    int i;
    for(i=0; i<n; i++)
    {
        if(strcmp(a[i].lname, lname)==0)
        {
            return i;
        }
        else
            return -1;
    }
}
int search_by_id (s1 a[], int n, char id[])
{
    int i;
    for(i=0; i<n; i++)
    {
        if(strcmp(a[i].id, id)==0)
        {
            return i;
        }
        else
            return -1;
    }
}


int search_by_golch (s1 a[], int n, float golch )
{
    int i;
    for(i=0; i<n; i++)
    {
        if(golch == a[i].golch)
            return  i;
        else
            return  -1;
    }
}


void sort_by_golch (s1 a[], int n)
{
    int i,j;
    char tmp[25];
    float f;
    for(i=0; i<n; i++)
    {
        for(j=i+1; j<n; j++)
        {
            if(a[i].golch<a[j].golch)
            {
                strcpy(tmp, a[i].fname);
                strcpy(a[i].fname, a[j].fname);
                strcpy(a[j].fname, tmp);
                strcpy(tmp, a[i].lname);
                strcpy(a[i].lname, a[j].lname);
                strcpy(a[j].lname, tmp);
                strcpy(tmp, a[i].id);
                strcpy(a[i].id, a[j].id);
                strcpy(a[j].id, tmp);
                f=a[i].golch;
                a[i].golch=a[j].golch;
                a[j].golch=f;


            }
        }
    }
}




int main()
{
    s1 a[100];
    int n, cmd, idx;
    printf("Oyutnii too : ");
    scanf( "%d", &n) ;
    read_students(a, n) ;
    print_students(a, n) ;
    char fname[20], lname[20], id[20];
    float golch ;
    while (1)
    {
        printf( "1: Search by name, 2: search by last name, 3: search by ID number, 4: Search by GPA, 5: Sort by GPA, 6: Print, 7: Exit \n" ) ;
        scanf( "%d", &cmd) ;
        if(cmd == 1)
        {
            printf( "First name : " ) ;
            scanf( "%s", fname) ;
            idx = search_by_fname(a, n, fname) ;
            if(idx == -1)
                printf( "No match\n" ) ;
            else
                print(a[idx] ) ;
        }
        else if(cmd == 2)
        {
            printf ( "Last Name : " ) ;
            scanf ( "%s", lname) ;
            idx = search_by_lname (a, n, lname) ;
            if( idx == -1)
                printf ( "No match\n" ) ;
            else
                print (a[idx]) ;
        }
        else if(cmd == 3)
        {
            printf ( "ID number : " ) ;
            scanf ( "%s", id ) ;
            idx = search_by_id (a, n, id ) ;
            if( idx == -1)
                printf( "No match\n" ) ;
            else
                print(a[idx] ) ;
        }
        else if(cmd == 4)
        {
            printf( "GPA: " ) ;
            scanf( "%f ", &golch ) ;
            idx = search_by_golch(a, n, golch ) ;
            if(idx == -1)
                printf ("No match\n") ;
            else
                print(a[idx]) ;
        }
        else if(cmd == 5)
            sort_by_golch(a, n) ;
        else if(cmd == 6)
            print_students(a, n) ;
        else
            break;
    }
    return 0;
}
]

Does anyone know why does this issue persist? Any help would be appreciated!

Would compiler are you using? It would be best if you simply looked at compiler warnings to iron out all errors.

Code:

    for(i=0; i<n; i++)
    {
        if(strcmp(a[i].fname, fname)==0)
        {
            return i;
        }
        else
            return -1;
    }

This is probably not the logic you want. This loop with always return on its first iteration – think about it.

error: 'print' was not declared in this scope on line 149 159 169 179;

Code:

prog.c: In function 'read_students':
prog.c:22:17: warning: format '%s' expects argument of type 'char *', but argument 2 has type 'char (*)[20]' [-Wformat=]
   22 |         scanf("%s %s %s %f",&a[i].fname, &a[i].lname, &a[i].id, &a[i].golch);
      |                ~^           ~~~~~~~~~~~
      |                 |           |
      |                 char *      char (*)[20]
prog.c:22:20: warning: format '%s' expects argument of type 'char *', but argument 3 has type 'char (*)[20]' [-Wformat=]
   22 |         scanf("%s %s %s %f",&a[i].fname, &a[i].lname, &a[i].id, &a[i].golch);
      |                   ~^                     ~~~~~~~~~~~
      |                    |                     |
      |                    char *                char (*)[20]
prog.c:22:23: warning: format '%s' expects argument of type 'char *', but argument 4 has type 'char (*)[10]' [-Wformat=]
   22 |         scanf("%s %s %s %f",&a[i].fname, &a[i].lname, &a[i].id, &a[i].golch);
      |                      ~^                               ~~~~~~~~
      |                       |                               |
      |                       char *                          char (*)[10]
prog.c: In function 'main':
prog.c:148:17: warning: implicit declaration of function 'print'; did you mean 'printf'? [-Wimplicit-function-declaration]
  148 |                 print(a[idx] ) ;
      |                 ^~~~~
      |                 printf
prog.c: In function 'search_by_fname':
prog.c:49:1: warning: control reaches end of non-void function [-Wreturn-type]
   49 | }
      | ^
prog.c: In function 'search_by_lname':
prog.c:64:1: warning: control reaches end of non-void function [-Wreturn-type]
   64 | }
      | ^
prog.c: In function 'search_by_id':
prog.c:77:1: warning: control reaches end of non-void function [-Wreturn-type]
   77 | }
      | ^
prog.c: In function 'search_by_golch':
prog.c:90:1: warning: control reaches end of non-void function [-Wreturn-type]
   90 | }
      | ^
/tmp/cc8YluFe.o: In function `main':
prog.c:(.text+0x78d): undefined reference to `print'
prog.c:(.text+0x842): undefined reference to `print'
prog.c:(.text+0x8f7): undefined reference to `print'
prog.c:(.text+0x9ad): undefined reference to `print'