Question

I need to read string of characters (with spaces) and reverse it.

First i read a string of characters from console.

char array[100];

for(int i = 0; i < sizeof(array); i++)
    array[i] = '0';

for(int i = 0; i < sizeof(array); i++)
    cout<<array[i]<<" ";

cout<<"\n\nenter your string: ";

cin.getline(array, 100);

cout<<"\n";

for(int i = 0; i < sizeof(array); i++)
    cout<<array[i]<<" ";   

Then i create and fill indexes array. (to remember space spots)

cout<<"\n\nindexes: ";

int indexes[20];
for(int i = 0; i < 20; i++)
{
    indexes[i] = 0;
}

// filling the indexes array
int j = 0;
for(int i = 0; i < sizeof(array); i++)
{
    if(array[i] == '0') break;
    if(array[i] == ' ')  indexes[j++] = i;
}   
// validating indexes array
for(int i = 0; i < sizeof(indexes); i++)
{
    //if(indexes[i] == 0) break;
    cout<<indexes[i]<<" ";
}  

Here is the begining of my (i guess not smart) algorythm. I want to reverse first word.
Seems like this chunk never executes. Why?

// first word
int j1 = indexes[0]-1;
for(int i = 0; i > indexes[0]; i++)     
{
    new_array[i] = array[j1-i];
            cout<<"\naction\n";
}

Print new_array to console:

for(int x = 0; x < sizeof(new_array); x++)
{
    if(new_array[x] == '0') break;
    cout<<new_array[x]<<" ";
}  

The result is:

0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

enter your string: this is my string

t h i s i s m y s t r i n g 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

indexes: 4 7 10 17 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 -858993460 -858993460 100 -85
8993460 -858993460 100 -858993460 -858993460 100 -858993460 -858993460 193628786
0 544434464 1931508077 1852404340 805314663 808464432 808464432 808464432 808464
432 808464432 808464432 808464432 808464432 808464432 808464432 808464432 808464
432 808464432 808464432 808464432 808464432 808464432 808464432 808464432 808464
432 -858993460 -742139265 6421640 18244041 1 9932784 9928256 -742139185 0 0 2129
674240 -1920 570026249 0 6422528 0 6421580 0 6421712 18223374 -759898201 0 64216
48 18244541

new array:

Why the indexes array contains these numbers after zeros? It’s length is only 20.
And why the new_array is not printed?

I know that my solution is very very cumbersome)

Answer 1

Your intuition is right: the loop isn’t being executed. The problem is in the line:

for(int i = 0; i > indexes[0]; i++)

The comparison should be i < indexes[0].