If switch contain another switch inside it then it is said as the Nested switch.
printf("case 1 is execute\n");
printf("case 2 is execute\n");
printf("case 3 is execute\n");
case 3 is execute
-In this program, we have a two variable a=1 and b='a'
-we check these value in different cases, then in first switch case 3 is match then it goes inside the other switch.
-In this way we perform a nested switch.