Toggle Menu

Control Flow

If Statements

Chooses between alternative actions based on value of Boolean expression.

if (Boolean_Expression_1) {
  Action1();
} else if (Boolean_Expression_2) {
  Action2();
} else {
  Action3();
}

Enclosing braces within each branch can be omitted if there is only one statement provided. Enclosing braces are used for compound statements. The else statement is also optional if not needed. If statements can also be nested.

Ternary Operator

Ternary operators are shorthand if-else statements that allows embedding of conditionals in expressions.
Syntax: var = (Boolean_Expression) ? True_Case : False_Case
e.g. Set the value of max to the maximum of n1 and n2: max = (n1 > n2) ? n1 : n2

Switch Statements

Similar to if statements but more convenient. Choice of branch is determined by a controlling expression given in paranthesis, which can only be one of:

1. bool
2. enum
3. int
4. char

switch (Controlling_Expression) {
  case Constant_1:
    Statement_Sequence_1
    break;
  case Constant_2:
    Statement_Sequence_2
    break;
  default:  // default branch if all other branches return false
    Default_Statement_Sequence
}

Loops

There are 3 types of loops in C++:

1. While loops - Most flexible, no restrictions.
2. Do-while loops - least flexible, always executes body at least once.
3. For loops - Iterates/counts through a defined range of values.

While Loops

while (Boolean_Expression) {  // Loops Condition
  Statements
}

Do-while Loops

do {
  Statements
} while (Boolean_Expression);  // Loop Condition

Comma Operator

The comma operator , evaluates a list of expressions and returns the value of the last expression. Used in for loops.
e.g. first = (first = 2, second = first + 1);

• first gets assigned the value 3
• second gets assigned the value 3

*Does not guarantee what order the expression will be evaluated. To guarantee the order, use parenthesis.

For Loops

For loops are used to step through a range of values, most commonly integers.

for (Initialization_Action; Boolean_Expression; Update_Action){
  Statements
}

The comma operator can be used to add multiple actions to the items in the loop condition. e.g.

for (Initialization_Action_1, Initialization_Action_2; Boolean_Expression; Update_Action){
  Statements
}

Break and Continue Statements

• break - forces the loop to exit immediately
• continue - skips rest of loop body