Using strcat in C

Question

Okay so I have the following Code which appends a string to another in C#, note that this is Just an example, so giving alternative string concatination met

Answer 1

I wonder why no one mentioned snprintf() from stdio.h yet. That's the C way to output multiple values and you won't even have to convert your primitives to strings beforehand.

The following example uses a stack allocated fixed-sized buffer. Otherwise, you have to malloc() the buffer (and store its size), which would make it possible to realloc() on overflow...

char buffer[1024];
int len = snprintf(buffer, sizeof(buffer), "%s %i", "a string", 5);
if(len < 0 || len >= sizeof(buffer))
{
    // buffer too small or error
}

Edit: You might also consider using the asprintf() function. It's a widely available GNU extension and part of TR 24731-2 (which means it might make it into the next C standard). The example from above would read

char * buffer;
if(asprintf(&buffer, "%s %i", "a string", 5) < 0)
{
    // (allocation?) error
}

Remember to free() the buffer when done using it!