Help!

Question

#include <iostream>
using namespace std;

int main() {
string a;
cin>>a;

for(int y=a.length();y=0;y--){
for(int i=0;i<a.length();i++){
a[i]=a[y-1];
}

}
cout<<a
return 0;
}

Why isn’t this code inversing the input string??

Answer 1

There is a problem with the logic. if you reverse string by its length , what will happen when both variables cross the middle? they will swap the swapped chars, no?

Example:
Start: [H][E][L][L][O]
v v
iter 1: [O][E][L][L][H]
v v
iter 2: [O][L][L][E][H]
vv
iter 3: [O][L][L][E][H]
v v
iter 4: [O][E][L][L][H]
v v
iter 5: [H][E][L][L][O]

i believe you must reverse up to middle (length / 2). you also need temporary variable to swap and not overwrite the characters.

i could do it your way except without nested loop, (but then you have to guard against division by 0) so i would do this instead:

size_t len = a.length();

for (size_t i = 0, end = len-1; i < len >> 1; i++) {
char swp = a[i];
a[i] = a[end - i];
a[end - i] = swp;
}

Answer 2

What is this code suppose to do and what is the input you are giving?

Answer 3

Nazeefa Labiba All you need to do is-

string a;
cin >> a;

for(int i=a.length()-1;i>=0;i--){
cout << a[i];
}

Answer 4

I am trying to make it inverse

Answer 5

I have tried to use >= in its place but still it is not working

Answer 6

plss help me