well, Call-by-value evaluation is the most common evaluation strategy, used in languages as far-ranging as C and Scheme. In call-by-value, the argument expression is evaluated, and the resulting value is bound to the corresponding variable in the function (usually by capture-avoiding substitution or by copying the value into a new memory region). If the function or procedure is able to assign values to its parameters, only the local copy is assigned -- that is, anything passed into a function call is unchanged in the caller's scope when the function returns.

In call-by-reference evaluation, a function receives an implicit reference to the argument, rather than a copy of its value. This means that the function can modify the argument, what will be seen by its caller. Call-by-reference therefore has the advantage of greater time- and space-efficiency (since arguments do not need to be copied), as well as the potential for greater communication between a function and its caller (since the function can return information using its reference arguments), but the disadvantage that a function must often take special steps to "protect" values it wishes to pass to other functions.

Answered by R.P. Singh , an ibibo Master, at 2:05 PM on July 23, 2008

well, Call-by-value evaluation is the most common evaluation strategy, used in languages as far-ranging as C and Scheme. In call-by-value, the argument expression is evaluated, and the resulting value is bound to the corresponding variable in the function (usually by capture-avoiding substitution or by copying the value into a new memory region). If the function or procedure is able to assign values to its parameters, only the local copy is assigned -- that is, anything passed into a function call is unchanged in the caller's scope when the function returns.

In call-by-reference evaluation, a function receives an implicit reference to the argument, rather than a copy of its value. This means that the function can modify the argument, what will be seen by its caller. Call-by-reference therefore has the advantage of greater time- and space-efficiency (since arguments do not need to be copied), as well as the potential for greater communication between a function and its caller (since the function can return information using its reference arguments), but the disadvantage that a function must often take special steps to "protect" values it wishes to pass to other functions.

Answered by Rocky , an ibibo Master, at 11:16 AM on July 22, 2008

The difference are given below-

The arguments passed to function can be of two types

1. Values passed 2. Address passed

The first type refers to call by value and the second type refers to call by reference.

For instance consider program1

main() { int x=50, y=70; interchange(x,y); printf(“x=%d y=%d”,x,y); } interchange(x1,y1) int x1,y1; { int z1; z1=x1; x1=y1; y1=z1; printf(“x1=%d y1=%d”,x1,y1); }

Here the value to function interchange is passed by value.

Consider program2

main() { int x=50, y=70; interchange(&x,&y); printf(“x=%d y=%d”,x,y); } interchange(x1,y1) int *x1,*y1; { int z1; z1=*x1; *x1=*y1; *y1=z1; printf(“*x=%d *y=%d”,x1,y1); }

Here the function is called by reference. In other words address is passed by using symbol & and the value is accessed by using symbol *.

The main difference between them can be seen by analyzing the output of program1 and program2.

The output of program1 that is call by value is

x1=70 y1=50 x=50 y=70

But the output of program2 that is call by reference is

*x=70 *y=50 x=70 y=50

This is because in case of call by value the value is passed to function named as interchange and there the value got interchanged and got printed as

x1=70 y1=50

and again since no values are returned back and therefore original values of x and y as in main function namely

x=50 y=70 got printed.

But in case of call by reference address of the variable got passed and therefore what ever changes that happened in function interchange got reflected in the address location and therefore the got reflected in original function call in main also without explicit return value. So value got printed as *x=70 *y=50 and x=70 y=50

Answered by Nagendra , an ibibo Master, at 6:24 AM on July 18, 2008

well, Call-by-value evaluation is the most common evaluation strategy, used in languages as far-ranging as C and Scheme. In call-by-value, the argument expression is evaluated, and the resulting value is bound to the corresponding variable in the function (usually by capture-avoiding substitution or by copying the value into a new memory region). If the function or procedure is able to assign values to its parameters, only the local copy is assigned -- that is, anything passed into a function call is unchanged in the caller's scope when the function returns.

In call-by-reference evaluation, a function receives an implicit reference to the argument, rather than a copy of its value. This means that the function can modify the argument, what will be seen by its caller. Call-by-reference therefore has the advantage of greater time- and space-efficiency (since arguments do not need to be copied), as well as the potential for greater communication between a function and its caller (since the function can return information using its reference arguments), but the disadvantage that a function must often take special steps to "protect" values it wishes to pass to other functions.

Answered by Yash , an ibibo Master, at 10:20 AM on July 17, 2008

well, Call-by-value evaluation is the most common evaluation strategy, used in languages as far-ranging as C and Scheme. In call-by-value, the argument expression is evaluated, and the resulting value is bound to the corresponding variable in the function (usually by capture-avoiding substitution or by copying the value into a new memory region). If the function or procedure is able to assign values to its parameters, only the local copy is assigned -- that is, anything passed into a function call is unchanged in the caller's scope when the function returns.

In call-by-reference evaluation, a function receives an implicit reference to the argument, rather than a copy of its value. This means that the function can modify the argument, what will be seen by its caller. Call-by-reference therefore has the advantage of greater time- and space-efficiency (since arguments do not need to be copied), as well as the potential for greater communication between a function and its caller (since the function can return information using its reference arguments), but the disadvantage that a function must often take special steps to "protect" values it wishes to pass to other functions.

Answered by .... ..... , an ibibo Master, at 7:54 PM on July 16, 2008

well, Call-by-value evaluation is the most common evaluation strategy, used in languages as far-ranging as C and Scheme. In call-by-value, the argument expression is evaluated, and the resulting value is bound to the corresponding variable in the function (usually by capture-avoiding substitution or by copying the value into a new memory region). If the function or procedure is able to assign values to its parameters, only the local copy is assigned -- that is, anything passed into a function call is unchanged in the caller's scope when the function returns.

In call-by-reference evaluation, a function receives an implicit reference to the argument, rather than a copy of its value. This means that the function can modify the argument, what will be seen by its caller. Call-by-reference therefore has the advantage of greater time- and space-efficiency (since arguments do not need to be copied), as well as the potential for greater communication between a function and its caller (since the function can return information using its reference arguments), but the disadvantage that a function must often take special steps to "protect" values it wishes to pass to other functions.

Answered by Raksha , an ibibo Master, at 9:32 AM on July 16, 2008

well, Call-by-value evaluation is the most common evaluation strategy, used in languages as far-ranging as C and Scheme. In call-by-value, the argument expression is evaluated, and the resulting value is bound to the corresponding variable in the function (usually by capture-avoiding substitution or by copying the value into a new memory region). If the function or procedure is able to assign values to its parameters, only the local copy is assigned -- that is, anything passed into a function call is unchanged in the caller's scope when the function returns.

In call-by-reference evaluation, a function receives an implicit reference to the argument, rather than a copy of its value. This means that the function can modify the argument, what will be seen by its caller. Call-by-reference therefore has the advantage of greater time- and space-efficiency (since arguments do not need to be copied), as well as the potential for greater communication between a function and its caller (since the function can return information using its reference arguments), but the disadvantage that a function must often take special steps to "protect" values it wishes to pass to other functions.

Answered by Ni .. , an ibibo Master, at 7:05 PM on July 15, 2008

well, Call-by-value evaluation is the most common evaluation strategy, used in languages as far-ranging as C and Scheme. In call-by-value, the argument expression is evaluated, and the resulting value is bound to the corresponding variable in the function (usually by capture-avoiding substitution or by copying the value into a new memory region). If the function or procedure is able to assign values to its parameters, only the local copy is assigned -- that is, anything passed into a function call is unchanged in the caller's scope when the function returns.

In call-by-reference evaluation, a function receives an implicit reference to the argument, rather than a copy of its value. This means that the function can modify the argument, what will be seen by its caller. Call-by-reference therefore has the advantage of greater time- and space-efficiency (since arguments do not need to be copied), as well as the potential for greater communication between a function and its caller (since the function can return information using its reference arguments), but the disadvantage that a function must often take special steps to "protect" values it wishes to pass to other functions.

Answered by Romi , an ibibo Master, at 11:40 AM on July 10, 2008

Call-by-value evaluation is the most common evaluation strategy, used in languages as far-ranging as C and Scheme. In call-by-value, the argument expression is evaluated, and the resulting value is bound to the corresponding variable in the function (usually by capture-avoiding substitution or by copying the value into a new memory region). If the function or procedure is able to assign values to its parameters, only the local copy is assigned -- that is, anything passed into a function call is unchanged in the caller's scope when the function returns.

In call-by-reference evaluation, a function receives an implicit reference to the argument, rather than a copy of its value. This means that the function can modify the argument, what will be seen by its caller. Call-by-reference therefore has the advantage of greater time- and space-efficiency (since arguments do not need to be copied), as well as the potential for greater communication between a function and its caller (since the function can return information using its reference arguments), but the disadvantage that a function must often take special steps to "protect" values it wishes to pass to other functions.

Answered by Madhurima , an ibibo Master, at 6:24 PM on July 07, 2008

Call-by-value evaluation is the most common evaluation strategy, used in languages as far-ranging as C and Scheme. In call-by-value, the argument expression is evaluated, and the resulting value is bound to the corresponding variable in the function (usually by capture-avoiding substitution or by copying the value into a new memory region). If the function or procedure is able to assign values to its parameters, only the local copy is assigned -- that is, anything passed into a function call is unchanged in the caller's scope when the function returns.

In call-by-reference evaluation, a function receives an implicit reference to the argument, rather than a copy of its value. This means that the function can modify the argument, what will be seen by its caller. Call-by-reference therefore has the advantage of greater time- and space-efficiency (since arguments do not need to be copied), as well as the potential for greater communication between a function and its caller (since the function can return information using its reference arguments), but the disadvantage that a function must often take special steps to "protect" values it wishes to pass to other functions.

Answered by Sharad Singh , an ibibo Master, at 6:16 PM on July 07, 2008