C code programming to reverse a number?

Answer 1

/*The coding style used in this source code is for convenience.

* It is widely used style of coding. */

#include <stdio.h>

void main() {

int number, modulus, reverse;

reverse = 0;

printf("Enter a number \n");

scanf("%d", &number);

while(number != 0) {

modulus = number % 10;

reverse = (reverse * 10) + modulus;

number =number / 10;

}

printf("The reversed number is %d", reverse);

getch();

}

Answer 2

int RevNum( int num )

{

const int base = 10;

int result = 0;

do

{

result *= base;

result += num % base;

} while( num /= base);

return( result );

}

Answer 3

There are two ways to reverse a number, as a string and as a value. The string form is required if you wish values with trailing zeroes to be written literally, so that 100 becomes 001. As a value, 100 becomes 1. Both forms are shown in the example below, which prints 10 random numbers in reverse.

#include<iostream>

#include<time.h>

int rev_as_num(int num)

{

int result = 0;

while( num )

{

result*=10;

result+=num%10;

num/=10;

}

return(result);

}

std::string rev_as_string(int num)

{

std::string result;

while( num )

{

result.push_back(num%10+'0');

num/=10;

}

return(result);

}

int main()

{

srand((unsigned) time(NULL));

for( int loop=0; loop<10; ++loop )

{

int num = rand(); // random number in range [0...RAND_MAX].

std::cout<<"Original:\t"<<num<<'\n'

<<"Reversed:\t"<<rev_as_string(num).c_str()<<'\n'

<<"As value:\t"<<rev_as_num(num)<<'\n'<<std::endl;

}

return(0);

}

Example output:

Original: 32254

Reversed: 45223

As value: 45223

Original: 15754

Reversed: 45751

As value: 45751

Original: 19691

Reversed: 19691

As value: 19691

Original: 10922

Reversed: 22901

As value: 22901

Original: 19449

Reversed: 94491

As value: 94491

Original: 24028

Reversed: 82042

As value: 82042

Original: 5746

Reversed: 6475

As value: 6475

Original: 29410

Reversed: 01492

As value: 1492

Original: 6189

Reversed: 9816

As value: 9816

Original: 20712

Reversed: 21702

As value: 21702

Answer 4

int RevNum( int num )

{

const int base = 10;

int result = 0;

int remain = 0;

do

{

remain = num % base;

result *= base;

result += remain;

} while( num /= base);

return( result );

}