How to create an array of strings from a given line in C?

Question

char a[100]="You are welcome";

Now how can I make the words in this line into array of strings?

char b[5][20];
strcpy(b[0],"you");
strcpy(b[1],"are");
strcpy(b[2],"welcome");

In this way, we can make array of strings.

But I want to do dynamically for any giving input ?

Please help...

in TCL, we can do by splitting the line [split $line " "] and then all words ll be in list elements. Is there any similar procedure in C? — sri
– sri, Commented Feb 20, 2016 at 8:31

tdao · Accepted Answer · 2016-02-20 09:05:24Z

3

strtok is your friend:

char a[] = "You are welcome";
char b[5][20] = {{0}};
char *pch;

pch = strtok( a," \t" );
int i = 0;
while( NULL != pch && i < 5)
{
    strcpy(b[i++], pch);
    pch = strtok( NULL, " \t\n" );
}

for( i = 0; i < 5; i++ )
{
    if( strlen(b[i]) > 0 )
    {
        printf( "b[%d] = %s\n", i, b[i] );
    }
}

Don't forget to #include <string.h>

As David C. Rankin pointed out. We can do away with strlen by just checking the first char not \0. So this'd be a better solution (note that the main while loop for strtok processing remains the same).

i = 0; 
while (*b[i]) 
{ 
    printf( "b[%d] = %s\n", i, b[i] ); 
    i++; 
}

edited Feb 20, 2016 at 9:05

answered Feb 20, 2016 at 8:37

tdao

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3 Comments

David C. Rankin Over a year ago

Since you properly initialize your b array, to iterate over all strings copied to the array (presuming you always leave b[4]... empty) , you can iterate over the strings with while (*b[i]) printf( "b[%d] = %s\n", i, b[i] ); (you can do the same with a dynamically allocated array of pointers-to-char by insuring you realloc before assigning a value to the last pointer).

David C. Rankin Over a year ago

No, you already initialized all characters to 0 with char b[5][20] = {{0}};, so simply checking whether the first char is something other than 0 allows you to avoid the additional call to strlen :) -- try it, replace your entire print loop with the while (*b[i]) loop. (you do need to insure you set i = 0; before the loop and i++ at the end)

David C. Rankin Over a year ago

Give it a try i = 0; while (*b[i]) { printf( "b[%d] = %s\n", i, b[i] ); i++; }

Shakeeb Ahmad · Accepted Answer · 2016-02-20 08:46:16Z

0

Reference:strtok

You can go for a "scanf" in place of "printf" inside while loop, and store the values in second array(b in your case)

 while (pch != NULL)   {
     printf ("%s\n",pch);
     pch = strtok (NULL, " ,.-");   }

answered Feb 20, 2016 at 8:46

Shakeeb Ahmad

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