CODEWITHSUNDEEP
c
studyembedded
studyembedded

Reputation: 73

Trying to use islower with array and pointers...getting error?

I tried arrays, pointers with string in the following program, but I don't know where I am going wrong.

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

// finding out the uper case and lower case in a string

int main()
{
    char *arr_1[] = {"CalCulaTor", "DoveTail", "MachiNing"};
    int i = 0, j;

    while(*(arr_1 + i) != '\0')
    {
        printf(" %d letter is %s ",i,islower(*(arr_1 + i)) ? "Lower case    " : "Not lower case");
        printf("\n");
        i++;
    }

    system("PAUSE");

    return 0;
}

Upvotes: 0

Views: 551

Answers (3)

Kludas
Kludas

Reputation: 571

char *arr_1[] is an array of pointers to char. You have to loop through your array of strings then loop over that string to get each individual element.

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

int main(void)
{
    char *arr_1[] = {"CalCulaTor", "DoveTail", "MachiNing"};
    size_t i, j;

    for (i = 0; i < 3; i++) {
        puts(arr_1[i]);
        for (j = 0; arr_1[i][j]; j++) {
            printf("'%d' element is %s.\n", j, islower(arr_1[i][j]) ? "Lowercase" : "Uppercase");
        }
        putchar('\n');
    }

    return 0;
}

The first loop will get your string (which is a pointer to char) as arr_1[i] then looping over that with another variable will give you an element in that pointer to char as arr_1[i][j].

Upvotes: 0

paulsm4
paulsm4

Reputation: 121799

A common idiom for an array of strings is to terminate the array with a NULL. For example:

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

// finding out the uper case and lower case in a string
char *arr_1[] = {
  "CalCulaTor", "DoveTail", "MachiNing", NULL
};

int main()
{
    char **a = arr_1;
    while(*a)
    {
        int i = 0;
        char *c = *a;
        printf ("%s:\n", c);
        while (*c) {
          printf(" %d letter(%c) is %s ", 
            i++,
            *c, 
            (islower(*c) ? "Lower case    " : "Not lower case"));
          c++;
        }
        printf("\n");
        a++;
    }
    system("PAUSE");
    return 0;
}

Upvotes: 0

Carl Norum
Carl Norum

Reputation: 225052

Your code looks OK to handle a single string, but you have an array of three strings. You need to add another loop to handle the iteration over that array.

Upvotes: 3

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