arrays - Validating a Barcode in C -

i beginner c coder working on program validate bar codes. far have code reads in 12 digit bar code. however, having trouble on attaching 12 digit input functions odd_value , even_value. need theses values validate bar code.

#include <stdio.h> #define array_size 12  int print_values(int* x)   { printf("\nstep 1: sum of odds times 3 \n" ); printf("step 2: sum of digits \n"); printf("step 3: total sum \n" ); printf("step 4: calculated check digit \n" ); printf("step 5: check digit , last digit \n" ); return 0; }   int odd_value()    { int sum_odd = (x[0] + x[2] + x[4] + x[6] + x[8] + x[10])*3; return sum_odd; }  int even_value()   { int sum_even = (x[1] + x[3] + x[5] + x[7] + x[9] + x[11]); return sum_even; }  int fill_array(){ int i; printf("enter barcode check. separate digits space >\n");   for(i=0; i<array_size; i++){     if(scanf("%d:", &x[i]) != 1) return 0; } return 1;  }          int main(){  int bar_code[array_size]; int i, last_digit, check_digit, odd, even;  if(fill_array(bar_code)) { printf("\nyou entered code: "); for(i=0; i<array_size; i++) printf("%d ", bar_code[i]); }  else {   puts("failed read"); }  odd = odd_value(); = even_value(); last_digit = odd + even; if(last_digit == 0)  {    check_digit = 0;   }   else  {       check_digit = 10 - last_digit;   }   print_values(bar_code);  if(check_digit == bar_code[array_size])   {   printf("barcode valid\n");     } else {          printf("barcode invalid\n");   }  return 0; } 

edit: updated code little bit bit confused. still working on it, there few main errors getting.

first error: function 'print_values' line 5: 'x' undeclared (first use in function) (each undeclared identifier reported once)

second error: function 'main' line 61: expected expression before 'const'

#include <stdio.h> #define array_size 12  void print_values(int odd_value(const int* x), int even_value(const int* x), int last_digit)   { printf("\nstep 1: sum of odds times 3 %d\n", odd_value(&x) ); printf("step 2: sum of digits %d\n", even_value(&x)); printf("step 3: total sum %d\n", last_digit);  printf("step 4: calculated check digit \n" ); printf("step 5: check digit , last digit \n" ); }  int odd_value(const int* x)    {  int sum_odd = (x[0] + x[2] + x[4] + x[6] + x[8] + x[10])*3;  return sum_odd; }  int even_value(const int* x)   { int sum_even = (x[1] + x[3] + x[5] + x[7] + x[9] + x[11]); return sum_even; }  int fill_array(int* x){    int i;    printf("enter barcode check. separate digits space >\n");  for(i=0; i<array_size; i++){     if(scanf("%d:", &x[i]) != 1) return 0; } return 1; }       int main(){  int bar_code[array_size]; int i, last_digit, check_digit, odd, even;  if(fill_array(bar_code)) { printf("\nyou entered code: "); for(i=0; i<array_size; i++) printf("%d ", bar_code[i]);  }  else {   puts("failed read");  }   odd = odd_value(bar_code);  = even_value(bar_code);  last_digit = odd + even;  if(last_digit == 0)  {  check_digit = 0;  }   else  {        check_digit = 10 - last_digit;  }   if(check_digit == bar_code[11])   {    printf("barcode valid\n");     } else {          printf("barcode invalid\n");    }    print_values(odd_value(const int* x), even_value(const int* x), last_digit);  return 0;   } 

edit:

i believe have 1 last question code. need last_digit equal last_digit in value sum. in main function have last_digit = sum, need manipulate last_digit in value sum. example, if sum = 72, last_digit 2.

#include <stdio.h> #define array_size 12  void print_values(int odd, int even, int sum, int last_digit, int check_digit)   {    printf("\nstep 1: sum of odds times 3 %d\n", odd );    printf("step 2: sum of digits %d\n", even);    printf("step 3: total sum %d\n", sum);    printf("step 4: calculated check digit %d\n", check_digit);      if(check_digit == last_digit) {    printf("step 5: check digit , last digit match\n" );   } else {    printf("step 5: check digit , last digit not match\n");   } }  int odd_value(const int* x)    {    int sum_odd = (x[0] + x[2] + x[4] + x[6] + x[8] + x[10])*3;    return sum_odd; }  int even_value(const int* x)   {    int sum_even = (x[1] + x[3] + x[5] + x[7] + x[9]);    return sum_even; }  int fill_array(int* x){    int i;    printf("enter barcode check. separate digits space >\n");     for(i=0; i<array_size; i++){        if(scanf("%d:", &x[i]) != 1) return 0;    }    return 1; }       int main(){   int bar_code[array_size];  int i, last_digit, check_digit, odd, even;   if(fill_array(bar_code)) {     printf("\nyou entered code: ");     for(i=0; i<array_size; i++) printf("%d ", bar_code[i]);  }  else {       puts("failed read");  }   odd = odd_value(bar_code);  = even_value(bar_code);   int sum = odd + even;  last_digit = sum;   if(last_digit == 0)  {     check_digit = 0;     }   else  {           check_digit = 10 - last_digit;     }   print_values(odd, even, sum, last_digit, check_digit);   if(check_digit == last_digit)   {     printf("barcode valid\n");      } else {            printf("barcode invalid\n");     }  return 0; } 

create argument pass (pointer first element of) array , use it.

int odd_value(const int *x) {     int sum_odd = (x[0] + x[2] + x[4] + x[6] + x[8] + x[10])*3;     return sum_odd; }  int even_value(const int *x) {     int sum_even = (x[1] + x[3] + x[5] + x[7] + x[9] + x[11]);     return sum_even; } 

calling them should this:

odd = odd_value(bar_code); = even_value(bar_code); 

note definition of fill_array() wrong , first line of should int fill_array(int *x){.

update: new code:

• define x in print_values(), or cannot use in function.
• your arguments calling print_values() invalid. write function name (identifier) pass function pointers.

i corrected arguments odd_value() , even_value() in print_values() have them suit added x.

improved code:

#include <stdio.h> #define array_size 12  void print_values(const int *x, int odd_value(const int* x), int even_value(const int* x), int last_digit) {     printf("\nstep 1: sum of odds times 3 %d\n", odd_value(x));     printf("step 2: sum of digits %d\n", even_value(x));     printf("step 3: total sum %d\n", last_digit);      printf("step 4: calculated check digit \n" );     printf("step 5: check digit , last digit \n" ); }  int odd_value(const int* x) {     int sum_odd = (x[0] + x[2] + x[4] + x[6] + x[8] + x[10])*3;     return sum_odd; }  int even_value(const int* x) {     int sum_even = (x[1] + x[3] + x[5] + x[7] + x[9] + x[11]);     return sum_even; }  int fill_array(int* x){     int i;     printf("enter barcode check. separate digits space >\n");      for(i=0; i<array_size; i++){         if(scanf("%d:", &x[i]) != 1) return 0;     }     return 1; }  int main(void){      int bar_code[array_size];     int i, last_digit, check_digit, odd, even;      if(fill_array(bar_code)) {         printf("\nyou entered code: ");         for(i=0; i<array_size; i++) printf("%d ", bar_code[i]);     }  else {         puts("failed read");     }      odd = odd_value(bar_code);     = even_value(bar_code);      last_digit = odd + even;      if(last_digit == 0)  {         check_digit = 0;     } else  {         check_digit = 10 - last_digit;     }      if(check_digit == bar_code[array_size - 1]) {         printf("barcode valid\n");     } else {         printf("barcode invalid\n");     }      print_values(bar_code, odd_value, even_value, last_digit);      return 0; }