integer array to string

[a.mlw.walker]

I have an array of integers (binary[4]) and I want to put the contents into a string i.e
binary[0] = 1
binary[1] = 0
binary[2] = 1
binary[3] = 1
and i want a string
str = 1011
I thought of doing this

char str[50] //buffer size so never overflow
sprintf( str, "%d%d%d%d", binary[0],binary[1],binary[2],binary[3] );

But I dont always know the size of binary and anymore than 4 and i dont want to have to type it in How can I do it in a loop because

for i = 0;i<5;i++
{
sprintf( str, "%d", binary[i]);
}

just overwrites it

[DaveH]

Look at strcat

[anduril462]

Or, since you know each number will be exactly one digit, you can sprintf into the middle of the string:

for (i = 0; i < 5; i++) {
    sprintf(&str[i], "%d", binary[i]);
}

Each time through the loop, you will write one digit, followed by a null. You will overwrite the previous null terminator with each iteration, but the final one will remain, leaving you with a proper string.

[itCbitC]

Initialize str[] to NULL, then supply it as an argument to sprintf():

for (i = 0; i < 4; i++)
    sprintf(str, "%s%d", str, binary[i]);

[anduril462]

Initialize str[] to NULL, then supply it as an argument to sprintf():

for (i = 0; i < 4; i++)
    sprintf(str, "%s%d", str, binary[i]);

Not such a good idea:

NOTES
Some programs imprudently rely on code such as the following


sprintf(buf, "%s some further text", buf);


to append text to buf. However, the standards explicitly note that the results are undefined if source and destination buffers overlap when calling sprintf(), snprintf(),
vsprintf(), and vsnprintf().

[itCbitC]

Not such a good idea:

Gotcha!