I wrote the code correctly, but it was showing errors. Then I opened your vid, and then I checked the code. It was correct for me. Could you tell what Is wrong in this code: #include int main() { int Number1; int Number2; int Operator; printf("*****************Welcome******************* ");//Welcome screen printf("What do you want to do "); printf("Example: Add[+], Substract[-], Divide[/], Multiply[*], Square[s], Qube[c]: "); scanf("%d", &Operater); printf("Enter first number: "); scanf("%d", &Number1); printf("Enter second number: "); scanf("%d", &Number2); switch(Operator) { case 1 : printf("%d + %d = %d",Number1,Number2,Number1+Number2); break; } return 0; } It is now showing no errors, but no answers are coming. Next day: #include int main() { int a,b,choice; printf("*****************Welcome******************* ");//Welcome screen printf("What do you want to do "); printf("Enter first number: "); scanf("%d", &a); printf("Enter second number: "); scanf("%d", &b); printf("Example: Add[+], Substract[-], Divide[/], Multiply[*], Square[s], Qube[c]: "); scanf("%s", &choice); switch(choice) { case 1: printf ("%d + %d = %d ",a,b,a+b); break; case 2: printf ("%d - %d = %d ",a,b,a-b); break; case 3: printf ("%d x %d =%d ",a,b,a*b); break; case 4: printf ("%d / %d = %d ",a,b,a/b); break; } return 0; } the same thing coming. Please reply what is wrong