Thread: Prob with my GPA calculator

The program ends after I input the last mark(the programming applications mark)I dunno y.

Code:

#include<stdio.h>
#include<math.h>
int
main()
{
      double esp,math,circuits,solid,art,pc,total,gpa;
    
      printf("\nEnter ESP3 mark :");
      scanf("%lf", &esp);
      printf("\nEnter Maths3 mark :");
      scanf("%lf", &math);
      printf("\nEnter Electrical Circuits 1 mark :");
      scanf("%lf", &circuits);
      printf("\nEnter Solid State Electronics mark :");
      scanf("%lf", &solid);
      printf("\nEnter Programming Applications mark :");
      scanf("%lf", &pc);
      
      if(esp>=90)
      esp=3*4.00;
      else
      if(90>esp>=85)
      esp=3*3.66;
      else
      if(85>esp>=80)
      esp=3*3.33;
      else
      if(80>esp>=75)
      esp=3*3.00;
      else 
      if(75>esp>=70)
      esp=3*2.66;
      else
      if(70>esp>=65)
      esp=3*2.33;
      else
      if(65>esp>=60)
      esp=3*2.00;
      else
      if(60>esp>=55)
      esp=3*1.66;
      else
      if(55>esp>=53)
      esp=3*1.33;
      else
      if(53>esp>=50)
      esp=3*1.00;
      else
      esp=3*0;
      
      
      
      if(math>=90)
      math=3*4.00;
      else
      if(90>math>=85)
      math=3*3.66;
      else
      if(85>math>=80)
      math=3*3.33;
      else
      if(80>math>=75)
      math=3*3.00;
      else 
      if(75>math>=70)
      math=3*2.66;
      else
      if(70>math>=65)
      math=3*2.33;
      else
      if(65>math>=60)
      math=3*2.00;
      else
      if(60>math>=55)
      math=3*1.66;
      else
      if(55>math>=53)
      math=3*1.33;
      else
      if(53>math>=50)
      math=3*1.00;
      else
      math=3*0;
      
      
      
      if(circuits>=90)
      circuits=3*4.00;
      else
      if(90>circuits>=85)
      circuits=3*3.66;
      else
      if(85>circuits>=80)
      circuits=3*3.33;
      else
      if(80>circuits>=75)
      circuits=3*3.00;
      else 
      if(75>circuits>=70)
      circuits=3*2.66;
      else
      if(70>circuits>=65)
      circuits=3*2.44;
      else
      if(65>circuits>=60)
      circuits=3*2.00;
      else
      if(60>circuits>=55)
      circuits=3*1.66;
      else
      if(55>circuits>=53)
      circuits=3*1.33;
      else
      if(53>circuits>=50)
      circuits=3*1.00;
      else
      circuits=3*0;
     
      
      
      if(solid>=90)
      solid=3*4.00;
      else
      if(90>solid>=85)
      solid=3*3.66;
      else
      if(85>solid>=80)
      solid=3*3.33;
      else
      if(80>solid>=75)
      solid=3*3.00;
      else 
      if(75>solid>=70)
      solid=3*2.66;
      else
      if(70>solid>=65)
      solid=3*2.33;
      else
      if(65>solid>=60)
      solid=3*2.00;
      else
      if(60>solid>=55)
      solid=3*1.66;
      else
      if(55>circuits>=53)
      circuits=3*1.33;
      else
      if(53>circuits>=50)
      circuits=3*1.00;
      else
      circuits=3*0;
     
      
      
      if(art>=90)
      art=3*4.00;
      else
      if(90>art>=85)
      art=3*3.66;
      else
      if(85>art>=80)
      art=3*3.33;
      else
      if(80>art>=75)
      art=3*3.00;
      else 
      if(75>art>=70)
      art=3*2.66;
      else
      if(70>art>=65)
      art=3*2.33;
      else
      if(65>art>=60)
      art=3*2.00;
      else
      if(60>art>=55)
      art=3*1.66;
      else
      if(55>art>=53)
      art=3*1.33;
      else
      if(53>art>=50)
      art=3*1.00;
      else
      art=3*0;
      
      
      
      if(pc>=90)
      pc=3*4.00;
      else
      if(90>pc>=85)
      pc=3*3.66;
      else
      if(85>pc>=80)
      pc=3*3.33;
      else
      if(80>pc>=75)
      pc=3*3.00;
      else 
      if(75>pc>=70)
      pc=3*2.66;
      else
      if(70>pc>=65)
      pc=3*2.33;
      else
      if(65>pc>=60)
      pc=3*2.00;
      else
      if(60>pc>=55)
      pc=3*1.66;
      else
      if(55>pc>=53)
      pc=3*1.33;
      else
      if(53>pc>=50)
      pc=3*1.00;
      else
      pc=3*0;
            
      total=esp+pc+circuits+solid+art+math;
      gpa=total/18;
      
      if(gpa>=3.4)
      printf("Excellent");
      else
      if(3.4>gpa>=2.8)
      printf("Very Good");
      else
      if(2.8>gpa>=2.4)
      printf("Good");
      else
      if(2.4>gpa>=2.0)
      printf("Weak");
      return (0);
}

You have throughout your code constructs like:

Code:

 if(3.4>gpa>=2.8)

While this is legal C, it's not doing what you think it is. What it will do is first evaluate 3.4>gpa. If 3.4 is greater than gpa, it will evaluate to 1. If 3.4 is not greater than gpa, it will evaluate to 0. It will then take the result of that first expression, and apply it >=2.8. So it will either be 1>=2.8 or 0>=2.8. Both of which evaluate to 0, or false. The correct code for the above is:

Code:

if (3.4>gpa && gpa>=2.8)

Or, probably more readably:

Code:

if (gpa < 3.4 && gpa >= 2.8)

Thanks alot it worked