The assignment operator = assigns a value to a variable / object:
int main() /*from w ww . j a v a 2s .co m*/ { char mychar = 'c'; // define a char variable mychar mychar = 'd'; // assign a new value to mychar int x = 123; // define an integer variable x x = 456; // assign a new value to x int y = 789; // define a new integer variable y y = x; // assing a value of x to it }