The way if statements can be nested, similarly whiles and for's can also be nested. To understand how nested loops work, look at the program given below:

\* C Program to show the use of Nesting of Loop *\

# include < stdio.h >

int main( )

{

int r, c, sum ;

for ( r = 1 ; r <= 3 ; r++ )

{

for ( c = 1 ; c <= 2 ; c++ )

{

sum = r + c ;

printf("\n r = %d c = %d sum = %d ", r, c, sum) ;

}

}

return ( 0 );

}

r = 1 c = 1 sum = 2

r = 1 c = 2 sum = 3

r = 2 c = 1 sum = 3

r = 2 c = 2 sum = 4

r = 3 c = 1 sum = 4

r = 3 c = 2 sum = 5