Declaring Variables in C

Before you use a variable in a C program you must declare it. The tradition in C is to declare all variables using lower case and to use the underscore as the separator.

int num_of_hours;

float rate_of_pay;

• In C it is acceptable to declare more than one variable on the same line

double ytd_tot_gross, ytd_tot_fedwh, ytd_tot_statewh;

• Variables may be declared as Global Variables or Local variables. A Global variable is declared outside of any function and is “known” to every function in the program. A variable declared in a function is “known” only to that function.
• C does NOT assign an initial value automatically. The programmer is responsible for placing a value in a variable. If no value is assigned to the variable whatever value currently stored in the memory allocated for that variable remains, no error is generated at compile or run time. A variable may be initialized when it is declared.

double ytd_tot_gross = 0;