C Language Zemi

if statement --conditional branch

I will explain about conditional branching in C language.

if statement

Use a
if statement to do a conditional branch.

if (condition) {
  // Processing to be executed when the conditions are met
}

As for the truth value in C language, 0 is false and other values ​​are true. NULL is defined as 0 in C, so it is false.

This is a sample if statement.

The comparison operator is 1 if it is satisfied and 0 if it is not.

#include <stdio.h>
#include <stdint.h>

int main (void) {
  int32_t flag = 1;
  
  if (flag == 1) {
    printf("1 OK\n");
  }
}

Output result.

1 OK

else if statement

If you want to write multiple conditions, use else if statement . You can write multiple else if statements.

if (condition 1) {
  // Processing to be executed when condition 1 is met
}
else if (condition 2) {
  // Processing to be executed when condition 2 is met
}
else if (condition 3) {
  // Processing to be executed when condition 3 is met
}

This is a sample of else if statement.

#include <stdio.h>
#include <stdint.h>

int main (void) {
  int32_t flag = 2;
  
  if (flag == 1) {
    printf("1 OK\n");
  }
  else if (flag == 2) {
    printf("2 OK\n");
  }
}

Output result.

2 OK

else statement

If you want to execute the process when the condition is not met, use the else statement.

if (condition) {
  // Processing to be executed when the conditions are met
}
else {
  // Processing to be executed when the condition is not met
}

if (condition 1) {
  // Processing to be executed when condition 1 is met
}
else if (condition 2) {
  // Processing to be executed when condition 2 is met
}
else if (condition 3) {
  // Processing to be executed when condition 3 is met
}
else {
  // Processing when all the above conditions are not met
}

This is a sample of the else statement.

#include <stdio.h>
#include <stdint.h>

int main (void) {
  int32_t flag = 3;
  
  if (flag == 1) {
    printf("1 OK\n");
  }
  else if (flag == 2) {
    printf("2 OK\n");
  }
  else {
    printf("Not OK\n");
  }
}

Output result.

Not OK