I need to get the correct answer for the following program for two integer ( one must be large like b)
please help.Code:#include<stdio.h> #include<conio.h> void main() { int long a, b, results; a=1234; b=19887815769532909; results= (0.5)*(a+b)*(a+b+1)*b; printf("%d",results); getch(); }
This code seems suspicious. What compiler and what OS are you using?
"19887815769532909" doesn't fit inside a 32-bit integer, and your "long int" probably is 32-bit, seeing the results you're getting. Use "long long" instead, assuming your compiler supports it.
Devoted my life to programming...
First of all, main() should be defined as:
"int long" should be just "long int" or better "long".Code:int main(void) { // ... }
your prinf() statement for printing a long should be:
or if you use a "long long":Code:printf("%ld",results);
Please stop using "conio.h" functions. They are Windows only and are NOT part of ANY C Standards!Code:printf("%lld",results);
Your expression should result in a double, not a long, since you are multiplying with "(0.5)". Assigning it to a long truncates the fractional part.
What is the answer you expect?
The answer won't fit in a 64-bit int, either. You could try a long double, but the answer won't be exact. If you need exact integer results then you need to use a bignum library (or implement the operations yourself).
The maximum unsigned 64-bit int is
18446744073709551615
The actual answer to your calculation is
3933066314831012816960565291086094692643810092064
The answer I get with a long double is
3933066314831012817088639772748881198425864929280
which is pretty pathetic (basically 64-bits precision, but with a floating binary point, of course).
Code:#include <stdio.h> int main() { long double a, b, result; a = 1234; b = 19887815769532909; result = 0.5 * (a + b) * (a + b + 1) * b; printf("%.0Lf", result); // getchar(); return 0; }
Last edited by algorism; 03-07-2017 at 05:17 PM.
