C Language Identifier Scope Block Scope
Example
An identifier has block scope if its corresponding declaration appears inside a block (parameter declaration in function definition apply). The scope ends at the end of the corresponding block.
No different entities with the same identifier can have the same scope, but scopes may overlap. In case of overlapping scopes the only visible one is the one declared in the innermost scope.
#include <stdio.h>
void test(int bar) // bar has scope test function block
{
int foo = 5; // foo has scope test function block
{
int bar = 10; // bar has scope inner block, this overlaps with previous test:bar declaration, and it hides test:bar
printf("%d %d\n", foo, bar); // 5 10
} // end of scope for inner bar
printf("%d %d\n", foo, bar); // 5 5, here bar is test:bar
} // end of scope for test:foo and test:bar
int main(void)
{
int foo = 3; // foo has scope main function block
printf("%d\n", foo); // 3
test(5);
printf("%d\n", foo); // 3
return 0;
} // end of scope for main:foo
