C语言if语句


if语句根据条件执行不同的代码块。

if (condition) {
    // Do something when `condition` is true
 }
 else {
    // Do something when `condition` is false
 }

condition为真,代码里面if部分执行,否则else执行。有时您需要添加第二个条件。为了便于阅读,您应该使用else if而不是嵌套if语句。

if (condition) {
    // Do something if `condition` is true
 }
 else if (anotherCondition) {
    // Do something if `anotherCondition` is ture
 }
 else {
    // Do something if `condition` AND `anotherCondition` is false
 }

请注意, elseelse if部分不是必需的,而if是必需的。

#include <stdio.h>

 int main () {

   // Local variable definition
   int a = 100;

   // Check the boolean condition
   if(a < 5) {
      // If condition is true then print the following
      printf("a is less than 5!\n" );
   }
   else {
      // If condition is false then print the following
      printf("a is not less than 5!\n" );
   }

   printf("Value of a is : %d\n", a);

   return 0;
 }

输出

-> a is not less than 5!
-> Value of a is : 100

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