Reverse An Array | C Programming Example

[rimaben]

I miss C! It was my first programming language in university, it should be learnt before all I think...

[xxyounn]

Thanks, really one of the most perfect explanation I've ever been taught.

[AlexSchneiderDev]

you're a great help of passing my cs50 course

[I-PixALbI-I]

"Advanced" way is without third variable:
Arithmetic operations: a = a + b; b = a - b; a = a - b;
XOR operations: a = a ^ b; b = a ^ b; a = a ^ b;

But somehow in my laptop looping through cycles for:
Arithmetic : 7.7 sec
XORing : 7.7 sec
Temp variable : 2.7 sec

Who could a thought?

[bizarrebeats]

I thought C didn't support pass by reference, and that you needed pointers for this kind of function?

[justcurious]

Nice 🙃:

void Reverse_array(int *array, int length){
int temp;
int middle = length/2;
for(int i = 0 ; i < middle ; i++){
temp = array[i];
array[i] = array[length-1-i];
array[length-1-i] = temp;
}
}
void Print_array(int *array, int length){
for(int i = 0 ; i < length ; i++){
printf("%d\t", array[i]);
}
printf("\n");
}

[bugrahankaramollaoglu]

I couldn't really understand the length / 2 part, could someone briefly explain?

[knightwik]

how about the case where the array has an odd integer of length? would you make another case for it?

[A.Safwat]

Thanks for the great explanation
Another way to do it:
#include <stdio.h>

int main()
{
int sizeOfArray, element;

printf("enter size of array: ");
scanf("%d", &sizeOfArray);
printf("enter elements of array: \n");
int ar1[sizeOfArray];
int ar2[sizeOfArray];
for(int i=0; i<sizeOfArray; i++){
scanf("%d", &element);
ar1[i]= element;
}
for(int i=0, counter=1; i<sizeOfArray; i++, counter++){
ar2[i]= ar1[sizeOfArray-counter];
printf("%d, ", ar2[i]);
}
return 0 ;
}

[simplex]

How do you know that without watching a video called "Reverse An Array | C Programming Example
" ???? Please I wanna be good at programming without looking at the internet.

[sarker_sudi]

Could you kindly do the same video except now you pass the array to the function and it returns a pointer to the reversed array we created. Thanks in advance

[vedaajayakumar]

Why use void instead of int while declaring function? I'm just learning so pls reply even if this might be dumb question

[Psc_Aspirant]

I couldn't understand (length-i-1)part. Could someone briefly explain?

[mdkanon-xt]

how about this ...?


#include <stdio.h>
int main()
{
int sz;
scanf("%d", &sz);
int a[sz], b[sz];
for (int i = 0, j = sz - 1; i < sz; i++, j--)
{
scanf("%d", &a[i]);
b[j] = a[i];
}
for (int i = 0; i < sz; i++)
{
printf("%d ", b[i]);
}

return 0;
}