1.2 KiB
1.2 KiB
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Short-Circuit Evaluation |
Short-Circuit Evaluation
The Short-Circuit evaluation consist in check or execute the second argument only if the first argument is not enough to determine the value of the expression.
You can do a short-circuit evaluation with && and || operators.
Example with && operator:
canOpenFile(filename) && openFile(filename); // If you can open the file then open it.
The example above is equivalent to:
if ( canOpenFile(filename) ) {
openFile(filename);
}
Example with || operator:
isServerOn || startServer(); // If the server is not on then start it.
The example above is equivalent to:
if ( !isServerOn ) {
startServer();
}
Keep it all together in real example
#include <stdio.h>
#include <stdlib.h>
char *getName();
int main(int argc, char *argv[]) {
// Get first argument passed via terminal
char *name = argv[1];
// If name is not passed via terminal then print message and then get the name
name || printf("Please give me your name:") && (name = getName());
printf("Hello %s\n", name);
}
char *getName() {
// Allocate memory
char *name = malloc(30);
scanf("%s", name);
return name;
}