Odtnhj

I want to convert string "hello world" to some integer value and get back "hello world" string from converted integer value. I tried but getting issue while converting int to string.

I converted the string to an integer using this code:

char str[50]; 
int i, len; int result=0; 
printf("Enter string to be converted: "); 
gets(str); 
len = strlen(str); 
for(i=0; i<len; i++) 
 result = result * 10 + ( str[i] - '0' ); 
 
printf("%dn", result);

and then I tried converting it back like this:

printf("%dn", result); 
int rem; int j = 0; 
char result_str[50]; 
while (result !=0) 
 result = result - '0' ; 
 rem = result%10 ; 
 result = result/10; 
 result_str[j] = 'a' + (rem -1); 
 printf("%c",result_str[j]); j++; 
 
printf("result string = %s",result_str);

Sample output:

$ ./a.out 
Enter string to be converted: hello
619663
619663
eccfhresult string = eccfh

When I try the string "hello world" I get a segmentation fault.

There is absolutely no way to convert a string to an int and then back again the way you want.

An int is typically 4 bytes, and you're using a char[50] which is 50 bytes. This means that an int can have 2³² different values, while a char[50] can have 2⁴⁰⁰ different values. So it is simply impossible to map them one to one.

Let's take an example outside the realm of code and computers and just focus on numbers. Can you imagine a method to convert a two-digit number to a one-digit number and back? If this was possible, then we would not need two digits in the first place. If such a method existed, you would be able to store an infinite amount of data in a single bit.

You can convert a char[4] to an int and back. It's actually really easy. This code will print abcd.

char str[4] = 'a', 'b', 'c', 'd';
// Convert to int
int result = *(int*) str;

char newstr[4];

// Convert back
char * ptr = (char*) &result;
for(int i=0; i<4; i++)
 newstr[i] = ptr[i];

printf("%.4sn", newstr);

Note that I completely ignored termination of the string, and just instructed printf to stop after four characters.

Oh, and never use the gets function. It's dangerous.