for
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Category
Syntax
for ( [<initialization>] ; [<condition>] ; [<increment>] ) <statement>
Description
The for statement implements an iterative loop.
<condition> is checked before the first entry into the block.
<statement> is executed repeatedly UNTIL the value of <condition> is false.
- Before the first iteration of the loop, <initialization> initializes variables for the loop.
- After each iteration of the loop, <increments> increments a loop counter. Consequently, j++ is functionally the same as ++j.
In C++, <initialization> can be an expression or a declaration.
The scope of any identifier declared within the for loop extends to the end of the control statement only.
A variable defined in the for-initialization expression is in scope only within the for-block. See the description of the -Vd option.
All the expressions are optional. If <condition> is left out, it is assumed to be always true.
Example
This example illustrates the use of the keyword for.
// An example of the scope of variables in for-expressions. // The example compiles if you use the -Vd option. #include <iostream> using std::cout; int main() { for (int i = 0; i < 10; i++) if (i == 8) cout << "\ni = " << i; return i; // Undefined symbol ‘i’ in function main(). }