Compare arrays of words in C

Question

How I can compare 2d arrays of char in C? I tried this

        Char **arr_1;
        Char **arr_2;

        ...// malloc. Its OK. 

        for (I=0; I<n; I++)
        {
           If (strcmp (arr_1[I],arr_2[I])==0)
                // do smth
        }

But it doesn't work . I'm not good in pointers.

Arrays have some array of words.

Ubuntu gcc

Without strcmp, the program works.

Thanks

also, did you miss to have the `{ }` to mark the scope of `for` loop? — Sourav Ghosh, Mar 27 '15 at 10:00
Have u placed the null character i.e. '\0' at the end of each word or string? — Yasir Majeed, Mar 27 '15 at 10:07
"*It does not work.*" Isn't a very detailed problem description. Please be more specific. Also comparing defintly only succeeds if the data to be compared had been setup propbery. We don not know if this is the case. — alk, Mar 27 '15 at 10:10
Also you need to do it in nested loop, because you might need to compare each word of arr_1 with each word of arr_2 — Yasir Majeed, Mar 27 '15 at 10:11
@alk ubuntu gcc compile it. But programm start and stop immediately. I dont know details ( — Artur Ganiev, Mar 27 '15 at 11:02
Not good at pointers? Become it.Take a look at [what are pointers](http://stackoverflow.com/a/5754/4185106) — moffeltje, Mar 27 '15 at 11:16
You might like to try debugging this yourself. To learn how to read here: http://ericlippert.com/2014/03/05/how-to-debug-small-programs/ — alk, Mar 27 '15 at 11:27

score 2 · Answer 1 · answered Mar 27 '15 at 16:54

You can do it.

char arr_1[10][10];
char arr_2[10][10];

int n;
scanf("%d",&n);

for(int i=0; i<n; i++)
{
    scanf(" %[^\n]",arr_1[i]);
    scanf(" %[^\n]",arr_2[i]);
}

for(int I=0; I<n; I++)
{
    if(strcmp (arr_1[I],arr_2[I])==0)
    {
        // do smth
    }
}

GorvGoyl · Accepted Answer · 2015-03-27T11:35:41.697

0

you must be allocating 2D dynamic array wrong.
consider this code:

int SIZE=5;

char **arr_1;
arr_1 = malloc(SIZE* sizeof(char *)); //initialising an array of pointers

char **arr_2;
arr_2 = malloc(SIZE* sizeof(char *)); //initialising an array of pointers

for(i=0;i<SIZE;i++)  
{
    printf(" Enter a name\n");  
    arr_1[i]=malloc(100*sizeof(char)); //for each pointer in this array allocate an array of characters
    scanf("%99s",arr_1[i]);
}

for(i=0;i<SIZE;i++)  
{
    printf(" Enter a name\n");  
    arr_2[i]=malloc(100*sizeof(char)); //for each pointer in this array allocate an array of characters
    scanf("%99s",arr_2[i]);
}


for(i=0;i<SIZE;i++)  
{
    if(strcmp(arr_1[i],arr_2[i])==0)
   //do smthing 
}

edited Mar 27 '15 at 11:35

answered Mar 27 '15 at 10:33

GorvGoyl

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I did it. Yes, for each row , and ubuntu gcc compile it. But programm start and stop immediately. – Artur Ganiev Mar 27 '15 at 10:59
This `scanf("%s", ...);` shall better be `scanf("%99s", ...);` – alk Mar 27 '15 at 11:31
Also `sizeof(char)` is `1` by definition. – alk Mar 27 '15 at 11:31

Compare arrays of words in C

2 Answers2