C语言菜鸟基础教程之条件判断

#include <stdio.h>

int main()
{
  int x = -1;
  if(x > 0)
  {
    printf("x is a positive number!\n");
  }
  else
  {
    printf("x is not a positive number!\n");
  }
          
  
  return 0;
}

#include <stdio.h>

int main()
{
  int x = 0;
  if(x > 0)
  {
    printf("x is a positive number!\n");
  }
  else if(x == 0)
  {
    printf("x is zero!\n");
  }
  else
  {
    printf("x is a negative number!\n");
  }       
  
  return 0;
}

#include <stdio.h>

int main()
{
  int x = 25;
  if(x < 0)
  {
    printf("x is less than 0\n");
  }
  if(x >= 0 && x <= 10)
  {
    printf("x belongs to 0~10\n");
  }
  else if(x >= 11 && x <= 20)
  {
    printf("x belongs to 11~20\n");
  }
  else if(x >= 21 && x <= 30)
  {
    printf("x belongs to 21~30\n");
  }
  else if(x >= 31 && x <= 40)
  {
    printf("x belongs to 31~40\n");
  }
  else
  {
    printf("x is greater than 40\n");
  }
  
  return 0;
}