My program has the goal of parsing the string "Ge34eks-f10or-Gee59ks". It does this by using strtok to split on delimiter '-' into three tokens Ge34eks, f10or, and Gee59ks. Each token is passed into num_extraction func with the goal of getting the numbers from each token: 34, 10, 59. I want to keep spaces between each token's numbers, so they will be stored in an array with a zero in between each number : [34, 0, 10, 0, 59]. When attempting to print array nothing appears. Note: The while loop handles the second and third token, so if it is commented out, the first token number,34,is correctly printed.

Specific issue: Nothing is printed? And no error is given Guesses: Either something wrong with my count variable or my array is not properly storing the numbers.

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


int* num_extraction(char* a, int* arr, int* index) 
{
    char* p = a;
    //int i = 0;
    while (*p)
    {  // While there are more characters to process...
        if (isdigit(*p) || ((*p == '-' || *p == ' ') && isdigit(*(p   1))))
        {
            // Found a number
            arr[*index] = strtol(p, &p, 10);  // Read number
            //printf("%d\n", val);          // and print it.
            *(index)  ;
        }
        else
        {
            // Otherwise, move on to the next character.
            p  ;
        }

    }
    return arr;

}

int main()
{
    char str[] = "Ge34eks-f10or-Gee59ks";
    int array[100] = { 0 };
    //int* p = array;
    int count = 0;
    int* q = &count;
 
 
    // Returns first token
    char *token = strtok(str, "-");
    num_extraction(token, array, q);
    count  = 2;
   
    // Keep printing tokens while one of the
    // delimiters present in str[].
    
    while (token != NULL) // problem starts here if loop is commented out first token number is printed
    {
        //printf("%s\n", token);
        token = strtok(NULL, "-");
        num_extraction(token, array, q);
        count  = 2;
    }
    
    for(int i = 0; i < count; i  )
    {
        printf("%d\n", array[i]);
    }
    //printf("%d\n", count);
    return 0;
}

Verion 2

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

char* char_extraction(char* a, char* arr, int* index) 
{
    char* p = a;
    
    for( int i = 0; i < strlen(p); i  )
    {
        printf("%s\n", "test"); // ISSUE: ONLY PRINTS TWICE?
        if(isalpha(p[i]))
        {
            
            arr[*index] = p[i];
            //printf("%c\n", arr[*index]);  
            *(index)  ;
        }
    }    
    return arr;

}


int main()
{
    char str[] = "Ge34eks-f10or-Gee59ks";
    int array[100] = { 0 };
    char array1[100] = "";
    int count1 = 0;
    int* r = &count1;
 
 
    // Returns first token
    char *token = strtok(str, "-");
    
    char_extraction(token, array1, r); // called once 
  
    count1  = 2;
   
    // Keep printing tokens while one of the
    // delimiters present in str[].
    
    
  
    while ((token = strtok(NULL, "-")) != NULL) 
    {
        
        char_extraction(token, array1, r); // should be called twice
        count1  = 2;
    }
    
    
    for(int i = 0; i < count1; i  )
    {
        printf("%c\n", array1[i]);
    }
    
    //printf("%d\n", count);
    return 0;
}

CodePudding user response：

look here - see inline comments

while (token != NULL) 
{
    // token not null here from last loop
    token = strtok(NULL, "-");
    // now token is null if last
    num_extraction(token, array, q);
    count  = 2;
}

you need to do

// get next token then test if NULL
while ((token = strtok(NULL, "-")) != NULL) 
{
    num_extraction(token, array, q);
    count  = 2;
}

or

// get next token then test if NULL
for(;;)
{
   token = strtok(NULL, "-");
    if(token == NULL) break;
    num_extraction(token, array, q);
    count  = 2;
}

or even

 while (token = strtok(NULL, "-")) 
    {
        //printf("%s\n", token);
        num_extraction(token, array, q);
        count  = 2;
    }