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The printf function takes an argument type, such as %d or %i for a signed int. However, I don't see anything for a long value.
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To print a long value, use the %ld format specifier. You can use the l prefix for x and o, too. So you would use %lx to print a long integer in hexadecimal format and %lo to print in octal format. C allows both uppercase and lowercase letters for constant suffixes, these format specifiers use just lowercase.
The parameters passed into printf() are known as arguments; these are separated commas. C Program 2.1 contains a printf() statement with only one argument, that is, a text string. This string is referred to as the message string and is always the first argument of printf().
#include <stdio. h> int main() { unsigned long long int num = 285212672; //FYI: fits in 29 bits int normalInt = 5; printf("My number is %d bytes wide and its value is %ul. A normal number is %d.
Put an l (lowercased letter L) directly before the specifier.
unsigned long n;
long m;
printf("%lu %ld", n, m);
I think you mean:
unsigned long n;
printf("%lu", n); // unsigned long
or
long n;
printf("%ld", n); // signed long
On most platforms, long and int are the same size (32 bits). Still, it does have its own format specifier:
long n;
unsigned long un;
printf("%ld", n); // signed
printf("%lu", un); // unsigned
For 64 bits, you'd want a long long:
long long n;
unsigned long long un;
printf("%lld", n); // signed
printf("%llu", un); // unsigned
Oh, and of course, it's different in Windows:
printf("%l64d", n); // signed
printf("%l64u", un); // unsigned
Frequently, when I'm printing 64-bit values, I find it helpful to print them in hex (usually with numbers that big, they are pointers or bit fields).
unsigned long long n;
printf("0x%016llX", n); // "0x" followed by "0-padded", "16 char wide", "long long", "HEX with 0-9A-F"
will print:
0x00000000DEADBEEF
Btw, "long" doesn't mean that much anymore (on mainstream x64). "int" is the platform default int size, typically 32 bits. "long" is usually the same size. However, they have different portability semantics on older platforms (and modern embedded platforms!). "long long" is a 64-bit number and usually what people meant to use unless they really really knew what they were doing editing a piece of x-platform portable code. Even then, they probably would have used a macro instead to capture the semantic meaning of the type (eg uint64_t).
char c; // 8 bits
short s; // 16 bits
int i; // 32 bits (on modern platforms)
long l; // 32 bits
long long ll; // 64 bits
Back in the day, "int" was 16 bits. You'd think it would now be 64 bits, but no, that would have caused insane portability issues. Of course, even this is a simplification of the arcane and history-rich truth. See wiki:Integer
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It depends, if you are referring to unsigned long the formatting character is "%lu". If you're referring to signed long the formatting character is "%ld".
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%ld see printf reference on cplusplus.com
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In case you're looking to print unsigned long long as I was, use:
unsigned long long n;
printf("%llu", n);
For all other combinations, I believe you use the table from the printf manual, taking the row, then column label for whatever type you're trying to print (as I do with printf("%llu", n) above).
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