Call by value
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The document discusses call by value and call by reference in functions. Call by value passes the actual value of an argument to the formal parameter, so any changes made to the formal parameter do not affect the actual argument. Call by reference passes the address of the actual argument, so changes to the formal parameter do directly modify the actual argument. An example program demonstrates call by value, where changing the formal parameter does not change the original variable.
Call by value
- 1. CALL BY VALUE & CALL BY REFERNCE TOPIC: PRESENTED BY G.DHARANI
- 2. THERE ARE TWO WAYS IN WHICH WE CAN PASS ARGUMENTS TO THE FUNCTION
- 3. CALL BY VALUE Value of actual arguments passed to the formal arguments. Any change made in the formal arguments does not effect the actual arguments. When function is called it does not affect the actual contents of the actual arguments.
- 4. #include <stdio.h> void call_by_value(int x) { printf("Inside call_by_value x = %d before adding 10.n", x); x += 10; printf("Inside call_by_value x = %d after adding 10.n", x); } int main() { int a=10; printf("a = %d before function call_by_value.n", a); call_by_value(a); printf("a = %d after function call_by_value.n", a); return 0; } EXAMPLE PROGRAM
- 5. OUTPUT OF THE PROGRAM a = 10 before function call_by_value. Inside call_by_value x = 10 before adding 10. Inside call_by_value x = 20 after adding 10. a = 10 after function call_by_value.
- 6. Actual and Formal arguments Arguments passed to the function during function call are known as actual arguments The arguments we use during a function definition are known as formal arguments.
- 7. For a function call to be valid the type, order and number of actual and formal arguments must always be same. Value of each of the actual arguments in the calling function is copied into the formal arguments of the called function. Changes made have no effect on the values of actual arguments in the calling function. Concept of Actual and Formal arguments
- 8. CALL BY VALUE CALL BY REFERENCE CALLING FUNCTION SENDS COPIES TO DATA. THE FORMAL PARAMETERS ARE ORDINARY VARIABLES. ATMOST ONLY ONE VALUES CAN BE SENT BACK TO THE CALLING FUNCTION. ACTUAL PARAMETERS ARE AFFECTED BY CHANGES MADE WITHIN THE FUNCTION. CALLING FUNCTION SENDS ADDRESS OF DATA. THE FORMAL PARAMETERS ARE POINTER VARIABLE. SEVERAL RESULTS CAN BE SENT BACK TO THE CALLING FUNCTION. DIRECT CHANGES ARE MADE TO THE ACTUAL PARAMETERS.