Converting int to string in C

Question

I am using the itoa() function to convert an int into string, but it is giving an error:

undefined reference to `itoa' collect2: ld returned 1 exit status 

What is the reason? Is there some other way to perform this conversion?

Answer 1

Use snprintf, it is more portable than itoa.

itoa is not part of standard C, nor is it part of standard C++; but, a lot of compilers and associated libraries support it.

Example of sprintf

char* buffer = ... allocate a buffer ... int value = 4564; sprintf(buffer, "%d", value); 

Example of snprintf

char buffer[10]; int value = 234452; snprintf(buffer, 10, "%d", value); 

Both functions are similar to fprintf, but output is written into an array rather than to a stream. The difference between sprintf and snprintf is that snprintf guarantees no buffer overrun by writing up to a maximum number of characters that can be stored in the buffer.

Answer 2

Use snprintf - it is standard an available in every compilator. Query it for the size needed by calling it with NULL, 0 parameters. Allocate one character more for null at the end.

int length = snprintf( NULL, 0, "%d", x ); char* str = malloc( length + 1 ); snprintf( str, length + 1, "%d", x ); ... free(str);