Investigate 9.4.
Zero is the value which C interprets as false. How could you use a logical operator so that C would interpret anything except zero as false, such as in an
if statement?
Section 9.7 Combining Multiple Logic Statements
The way to write the logical
AND in C is with two ampersand signs: &&
Compile and run the code below in your own C environment.
#include <stdio.h>
int main(void) {
int sunny = 8; /* on a scale of 1 to 10 */
int vacation = 1;
if ( (sunny>5) && vacation) {
printf("It\'s super sunny and I am on vacation! What could be better?\n");
} else {
printf("Ugh!\n");
}
return(0);
}
The way to write the logical
OR in C is with two vertical bars: ||
Compile and run the code below in your own C environment.
#include <stdio.h>
int main(void) {
int month = 8; /* month of the year*/
if ( (month<6) || (month>9)) {
printf("It\'s not summer unfortunately.\n");
} else {
printf("Look\'s like summer to me!\n");
}
return(0);
}
The way to negate a condition in C is to put an exclamation mark in front of it:
!(...)
Compile and run the code below in your own C environment.
#include <stdio.h>
int main(void) {
int month = 8; /* month of the year*/
if ( !((month>=6) && (month<=9)) ) {
printf("It's not summer unfortunately.\n");
} else {
printf("Look's like summer to me!\n");
}
return(0);
}
