CODEWITHSUNDEEP
carrays
yroc
yroc

Reputation: 966

C Program to Get Characters into Array and Reverse Order

I'm trying to create a C program that accepts a line of characters from the console, stores them in an array, reverses the order in the array, and displays the reversed string. I'm not allowed to use any library functions other than getchar() and printf(). My attempt is below. When I run the program and enter some text and press Enter, nothing happens. Can someone point out the fault?

#include <stdio.h>
#define MAX_SIZE 100

main()
{
    char c;                     // the current character
    char my_strg[MAX_SIZE];     // character array
    int i;                      // the current index of the character array

    // Initialize my_strg to null zeros
    for (i = 0; i < MAX_SIZE; i++)
    {
        my_strg[i] = '\0';
    }

    /* Place the characters of the input line into the array */
    i = 0;
    printf("\nEnter some text followed by Enter: ");
    while ( ((c = getchar()) != '\n') && (i < MAX_SIZE) )
    {
        my_strg[i] = c;
        i++;
    }

    /* Detect the end of the string */
    int end_of_string = 0;
    i = 0;
    while (my_strg[i] != '\0')
    {
        end_of_string++;
    }

    /* Reverse the string */
    int temp;
    int start = 0;
    int end = (end_of_string - 1);
    while (start < end)
    {
        temp = my_strg[start];   
        my_strg[start] = my_strg[end];
        my_strg[end] = temp;
        start++;
        end--;
    }

    printf("%s\n", my_strg);

}

Upvotes: 0

Views: 239

Answers (2)

Bayleef
Bayleef

Reputation: 195

I think you should look at your second while loop and ask yourself where my_string[i] is being incremented because to me it looks like it is always at zero...

Upvotes: 1

peval27
peval27

Reputation: 1309

It seems like in this while loop:

while (my_strg[i] != '\0')
{
    end_of_string++;
}

you should increment i, otherwise if my_strg[0] is not equal to '\0', that's an infinite loop. I'd suggest putting a breakpoint and look what your code is doing.

Upvotes: 2

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