Question

This loop won’t terminate if I add an OR conditional statement. If one is false, then it should terminate.

//global var

int x = 100;
    char *n= malloc (64);

void add(void)
{       

    do      
    {
        printf("Would you like to add 1? (y/n) ");
        fgets(n, 64, stdin);
            //removes newline
        n[strlen(n)-1] = '\0';
            x++;
    }       
//if I add || (x!=100) it keeps looping me even if I press "n"
//otherwise without it it works fine

        while((strncmp(n, "n", 1) != 0) || x!=100 );

        free(n);
}

Answer 1

At the bottom of your loop, you’re doing x++. Once you hit the while condition, x == 101, so your loop never terminates, x never equals 100 when the condition is being checked.

Perhaps you wanted:

while((strncmp(n, "n", 1) != 0) && x != 100);

Which would terminated the loop if either of the two conditions is false.

&& is the ‘logical and’ operator, || is the ‘logical or’ operator. To help you keep track, you can use a Truth Table to help you sort out the details. Logical and is the same as logical conjunction and logical or is the same as logical disjunction.