if( boolean_expression 1) { /* Executes when the boolean expression 1 is true */ if(boolean_expression 2) { /* Executes when the boolean expression 2 is true */ } }
[dywang@dyw219 zzz]$ cat if3.c #include <stdio.h> main() { int a; printf("Enter an integer: "); scanf("%d", &a); if ( a>10 ) { printf("%d > 10\n", a); if ( a<100) { printf("%d < 100\n", a); } } else { printf("a <= %d\n", a); } printf("a = %d\n", a ); }
[dywang@dyw219 zzz]$ gcc -o if3 if3.c
[dywang@dyw219 zzz]$ ./if3 Enter an integer: 5 a <= 5 a = 5
[dywang@dyw219 zzz]$ ./if3 Enter an integer: 49 49 > 10 49 < 100 a = 49
[dywang@dyw219 zzz]$ ./if3 Enter an integer: 200 200 > 10 a = 200