Why is my valid_triangle program from cs50 doesn't work? - c

Question

I have a problem with this code as I can't seem to find the problem? Here is the problem that I tried to solve: - Declare and write a function called valid_triangle that takes three real numbers representing the lengths of the three sides of a triangle as its arguments, and outputs either true or false, depending on whether those three lengths are capable of making a triangle.
Following rules about triangles:
A triangle may only have sides with a positive length.
The sum of the lengths of any two sides of the triangle must be greater than the length of the third side.
//includes
#include <stdio.h>
#include <cs50.h>
bool valid_triangle(float x, float y, float z);
int main (void)
{
float x = get_float("x:");
float y = get_float("y:");
float z = get_float("z:");
bool w = valid_triangle(x, y, z);
}
bool valid_triangle(float x, float y, float z)
{
// only positive sides
if (x <= 0 || y <= 0 || z <= 0)
{
return false;
printf("false\n");
}
// sum of the lengths of any two sides of the triangle must be greater than the length of the third side.
else if (x + y < z || x + z < y || y + z < x)
{
return false;
printf("false\n");
}
else
{
return true;
printf("True\n");
}
return 0;
}

Answer 1

For starters this if statement
else if (x + y < z || x + z < y || y + z < x)
is not correct, It should look like
else if (x + y <= z || x + z <= y || y + z <= x)
And statements after return statements like in this code snippet
return false;
printf("false\n");
do not have an effect. It seems you mean
printf("false\n");
return false;
Though the calls of printf should not be inside the function.
You could place only one call of printf in main like
bool w = valid_triangle(x, y, z);
printf( "%s\n", w == false ? "False" : "True" );
Also the last return statement within the function
return 0;
is redundant.
Here is a demonstrative program.
#include <stdio.h>
#include <stdbool.h>
bool valid_triangle(float x, float y, float z)
{
// only positive sides
if (x <= 0 || y <= 0 || z <= 0)
{
return false;
}
// sum of the lengths of any two sides of the triangle must be greater
// than the length of the third side.
else if ( x + y <= z || x + z <= y || y + z <= x)
{
return false;
}
else
{
return true;
}
}
int main(void)
{
float a = 4.0f, b = 5.0f, c = 6.0f;
printf( "%.1f, %.1f, %.1f are sides of a triangle - %s\n", a, b, c,
valid_triangle( a, b, c ) ? "true" : "false" );
return 0;
}
The program output is
4.0, 5.0, 6.0 are sides of a triangle - true

Answer 2

// This code should work as a solution for the valid_triangle program. Hope it helps
#include <cs50.h>
#include <stdio.h>
// first declare the function with the semi-colon at the end
bool valid_triangle(float x, float y, float z);
int main(void)
{
// Ask users for inputs
float a = get_float("Give me the first integer to form a triangle: ");
float b = get_float("Give me the second integer to form a triangle: ");
float c = get_float("Give me the third integer to form a triangle: ");
// function call
bool result=valid_triangle(a, b, c);
//set condition for your boolean variable 'result'
if (result == true)
{
printf("True \n");
}
else
{
printf("False \n");
}
}
//function definition, without any semi-colon at the end
bool valid_triangle(float x, float y, float z)
{
//checking if any of the sides is negative or equal to zero
if (x<=0 || y<=0 || z<=0)
{
return false;
}
// sum of the lengths of any two sides of the triangle must be greater than the length
//of the third side.
else if ((x+y<=z) || (x+z<=y) || (z+y<=x))
{
return false;
}
return true;
}