#INF00 ocurrs when cal. sum=(n/2)*(2*a+(n-1)*d)

[aryucc]

#include <stdio.h>
int main()
{ float sum, n, a, d, l;
n=l-a+1, d=1, a=1, l=100;
sum=(n/2)*(2*a+(n-1)*d);  
printf("The sum of the numbers from %f to %f is %f.", a, l, sum);
 
    fflush(stdin);
    printf("\n\nPlease press Enter to continue......");
    getchar ();
    return 0;
}

it is calculating 1+2+3+...+100=sum
why the sum becomes 1.#INF00???
PLZ HELP!!!!thz a LOT!!!

[sicarie]

n=l-a+1, d=1, a=1, l=100;
 

In this line right here, when you set n, what are the values of l and a?

[aryucc]

In this line right here, when you set n, what are the values of l and a?

that means i have to do it like the followings:

{ float sum, n, a, d, l;//n=no of term, a=first term, d=different, l=last term
d=1, a=1, l=100, n=l-a+1;
sum=(n/2)*(2*a+(n-1)*d);  
printf("The sum of the numbers from %f to %f is %f.", a, l, sum);

right???

thz so much.

[sicarie]

that means i have to do it like the followings:

{ float sum, n, a, d, l;//n=no of term, a=first term, d=different, l=last term
d=1, a=1, l=100, n=l-a+1;
sum=(n/2)*(2*a+(n-1)*d);  
printf("The sum of the numbers from %f to %f is %f.", a, l, sum);

right???

thz so much.

You might consider putting it on a separate line, just in case a compiler gets creative, but yes, you are not instantiating the values before you create them, which leads to undefined behavior.