Thread: Reverse string question - for loop

Could someone please explain exactly what the for statement in this problem is doing step by step?

Code:

#include <stdio.h>
#include <string.h>

int main()
{
    char string[100], reversestring[100];
    int x, y;
    
    printf("Enter the string to reverse:");
    scanf("%s", string);
    
    for (i=strlen(string)-1, x=0; i>=0; x--, y++){
        reversestring[y]=string[x]; }
    
    reversestring[y]='\0';
    
    printf("Your string %s reversed is %s \n", string, reversestring);


}

Originally Posted by benrogers

Could someone please explain exactly what the for statement in this problem is doing step by step?

It's reversing the string named "string", char by char.

Add a line of code to print string[x], and x, and see what it prints out. Use %c for string[x] and %d format for x, since it is an integer.

It actually does a whole lot of nothing, but I'll let the OP take a crack at exactly why that is.

Originally Posted by benrogers

Could someone please explain exactly what the for statement in this problem is doing step by step?

Code:

#include <stdio.h>
#include <string.h>

int main()
{
    char string[100], reversestring[100];
    int x, y;
    
    printf("Enter the string to reverse:");
    scanf("%s", string);
    
    for (i=strlen(string)-1, x=0; i>=0; x--, y++){
        reversestring[y]=string[x]; }
    
    reversestring[y]='\0';
    
    printf("Your string %s reversed is %s \n", string, reversestring);


}

Why don't you run it in a debugging utility and find out for yourself...

Hint: It actually does a whole lot of nothing.

Originally Posted by quzah

Too bad your hint is wrong. y is used uninitialized, so there is a really good chance that all this code just segfaults.
Quzah.

That and i is never decremented... letting x and y run wild...