How can I replace percent sign(%) with two % in C?

How can I replace percent sign(%) with two % in C?

i want to try replace Percent sign in a Char Array with two %% Signs.
Because a % Sign causes Problem, if I write as output Char Array.
Therefore Percent Sign must be replaced with two %% Signs without using
String.
char input[]="This is a Text with % Charakter"; // This Array causes Dump
because of '%'
//Therefore Percent Sign(%) must be replaced with two %%.