Section 15.10: goto

in this case if case 1 is satisfied then block 1 is executed , what we really want is only the block1 to be processed but instead once the block1 is processed remaining blocks,block2,block3 and blockdefault are also processed even though only case 1 was satified.To avoid this we use break at the end of each block like :

switch(condition){ case 1: block1;

break; case 2: block2;

break; case 3: block3;

break; default: blockdefault;

break;

}

so only one block is processed and the control moves out of the switch loop.

break can also be used in other conditional and non conditional loops like if,while,for etc;

example:

if(condition1){

....

if(condition2){

.......

break;

}

...

}

The continue instruction:

The continue instruction causes the program to skip the rest of the loop in the present iteration as if the end of the statement block would have been reached, causing it to jump to the following iteration.

The syntax is

continue;

Example consider the following :

for(int i=0;i<10;i++){ if(i%2==0)

continue; cout<<"\n @"<<i;

}

which produces the output:

@1 @3 @5 @7 @9

i this code whenever the condition i%2==0 is satisfied continue is processed,this causes the compiler to skip all the remaining code( printing @ and i) and increment/decrement statement of the loop gets executed.

goto STEP;

}

cout << "value of num : " << num << endl; num = num + 1;

}while( num < 10 );

output :

value of num : 1 value of num : 3 value of num : 5 value of num : 7 value of num : 9

whenever the condition num%2==0 is satisfied the goto sends the execution control to the beginning of the do-while loop.

The exit function:

exit is a function defined in cstdlib. The purpose of exit is to terminate the running program with an specific exit code. Its prototype is:

void exit (int exit code);

cstdlib defines the standard exit codes EXIT_SUCCESS and EXIT_FAILURE.

Section 15.12: return

Returns control from a function to its caller.

If return has an operand, the operand is converted to the function's return type, and the converted value is returned to the caller.

int f() { return 42;

}

int x = f(); // x is 42 int g() {

return 3.14;

}

int y = g(); // y is 3

If return does not have an operand, the function must have void return type. As a special case, a void-returning function can also return an expression if the expression has type void.

void f(int x) {

if (x < 0) return; std::cout << sqrt(x);

}

int g() { return 42; } void h() {

return f(); // calls f, then returns return g(); // ill-formed

}

When main returns, std::exit is implicitly called with the return value, and the value is thus returned to the