Manipulating strings in C with user input

Question

I am working on a program for my comp sci classes and the problem asks to take a command from the user and the string that. Then, use either "reverse " to reverse the string that follows or "create " to print the string that follows. The reverse output should keep the words reverse, then print the string that follows in reverse.

/* for Reverse command */
else if(strcmp(str,"reverse ") > 0)
{
    reverse(str);
    printf("Reverse of string: %s\n", str);
}

The following function is used to reverse the word:

void reverse(char *string)
{
    int length, i;
    char *begin, *end, temp;

    length = strlen(string);

    begin = string;
    end = string;

    for (i = 0 ; i < (length - 1) ; i++)
    end++;

    for (i = 0 ; i < length/2 ; i++)
    {
       temp = *end;
       *end = *begin;
       *begin = temp;

     begin++;
     end--;
    }
}

The output reverses all the words and prints. Is there a way to break off the reverse part of the string before it is passed to the reverse function?

Give a command: reverse hello world Reverse of string: dlrow olleh esrever — nerd4life
– nerd4life, Commented Nov 21, 2014 at 15:17
That's what's actually happening or what you expect? Please edit in your question. — bitcell
– bitcell, Commented Nov 21, 2014 at 15:19
Then all you have to do is to read 2 strings instead of 1.The first string will be the command(you don't reverse it), and the second string you will apply the reverse(). All this is assuming you read reverse hello world in one string. — bitcell
– bitcell, Commented Nov 21, 2014 at 15:21

Spikatrix · Accepted Answer · 2014-11-21 15:47:51Z

1

Before calling the function reverse, use

char *ptr=strchr(str,' ');
str=++ptr;

To cut off "reverse" from str.string.h needs to be included to use strchr.strchr returns a pointer to the first occurrence of the character ' ' in the string str, or NULL if the character is not found.ptr is incremented once before assigning it to str to remove the space from the string.

edited Nov 21, 2014 at 15:47

answered Nov 21, 2014 at 15:42

Spikatrix

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3 Comments

nerd4life Over a year ago

I get this error "incompatible types when assigning to type ‘char[200]’ from type ‘char *’"

nerd4life Over a year ago

My str variable is defined as str[200]

Spikatrix Over a year ago

@nerd4life ,Try strcpy(str,++ptr); instead of str=++ptr;

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