C Programming Code Examples

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Program to check valid triangle using nested if - best approach



Program to check valid triangle using nested if - best approach

Despite of easiness, the above code is messy and less readable. In above code printf("Triangle is not valid."); statement is unnecessarily repeated for various conditions. You can cut the extra printf("Triangle is not valid."); statement using a flag variable.

Let us suppose a temporary variable valid initialized with 0 indicating triangle is not valid. The main idea is to check triangle validity conditions and if triangle is valid then set valid variable to 1 indicating triangle is valid. Finally, check if(valid == 1) then triangle is valid otherwise not valid.
  
#include <stdio.h>  
  
int main()  
{  
    int side1, side2, side3; 

    /* Initially assume that the triangle is not valid */
    int valid = 0;
  
    /* Input all three sides of a triangle */  
    printf("Enter three sides of triangle: \n");  
    scanf("%d%d%d", &side1, &side2, &side3);  
      
    if((side1 + side2) > side3)  
    {  
        if((side2 + side3) > side1)  
        {  
            if((side1 + side3) > side2)
            {  
                /*
                 * If side1 + side2 > side3 and
                 *    side2 + side3 > side1 and
                 *    side1 + side3 > side2 then
                 * the triangle is valid. Hence set
                 * valid variable to 1.
                 */
                valid = 1;
            }  
        }
    }  
    
    /* Check valid flag variable */
    if(valid == 1)
    {
        printf("Triangle is valid.");
    }
    else
    {
        printf("Triangle is not valid.");
    }

    printf("Happy Codings - C Programming Language Code Examples");
    return 0;  
}