Question

how can i print a char array such i initialize and then concatenate to another char array? Please see code below

int main () {
char dest[1020];
char source[7]="baby";
cout <<"source: " <<source <<endl;
cout <<"return value: "<<strcat(dest, source) <<endl;
cout << "pointer pass: "<<dest <<endl;
return 0;
}

this is the output

source: baby
return value: v����baby
pointer pass: v����baby

basically i would like to see the output print

source: baby
return value: baby
pointer pass: baby

Answer 1

You haven’t initialized dest

char dest[1020] = ""; //should fix it

You were just lucky that it so happened that the 6th (random) value in dest was 0. If it was the 1000th character, your return value would be much longer. If it were greater than 1024 then you’d get undefined behavior.

Strings as char arrays must be delimited with 0. Otherwise there’s no telling where they end. You could alternatively say that the string ends at its zeroth character by explicitly setting it to 0;

char dest[1020];
dest[0] = 0;

Or you could initialize your whole array with 0’s

char dest[1024] = {};

And since your question is tagged C++ I cannot but note that in C++ we use std::strings which save you from a lot of headache. Operator + can be used to concatenate two std::strings