Single quotes vs. double quotes in C or C++

Question

When should I use single quotes and double quotes in C or C++ programming?

Answer 1

Use single quote with single char as:

char ch = 'a';

here 'a' is a char constant and is equal to the ASCII value of char a.

Use double quote with strings as:

char str[] = "foo";

here "foo" is a string literal.

Its okay to use "a" but its not okay to use 'foo'