Loop Constructs

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While Loops

While loops in C++ like those in Java can be used to create event- and count-controlled loops. The following function which sums a range of integers, illustrates a count-controlled loop in C++

int sumInts( int from, int to )
{
int sum = 0;
int i = from;
while( i <= to ) {
sum += i;
i++;
}
return sum;
}

Event-controlled loops are typically used when extracting data from files and for user interaction. The following function illustrates the use of an event-controlled loop to extract and sum positive integer values from the user.

int sumUserValues()
{
int sum = 0;
int value;

/* We must extract the first value before the loop. */
scanf( "%d", &value );
while( value > 0 ) {

/* We use the extracted value. */
sum += value;

/* Extract the next value from the user. */
scanf( "%d", &value );
}

return sum;
}

For Loops

Do-While Loops

Logical Constructs

Cpp Primer

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