That’s because %d expects an int but you’ve provided a float. Use %e/%f/%g to print the float. On why 0 is printed: The floating point number is converted to double before sending to printf. The number 1234.5 in double representation in little endian is 00 00 00 00 00 4A 93 40 A %d consumes … Read more
What you want is %.2f, not 2%f. Also, you might want to replace your %d with a %f 😉 #include <cstdio> int main() { printf(“When this number: %f is assigned to 2 dp, it will be: %.2f “, 94.9456, 94.9456); return 0; } This will output: When this number: 94.945600 is assigned to 2 dp, … Read more
I note that <system.h> is a non-standard header; I replaced it with <unistd.h> and the code compiled cleanly. When the output of your program is going to a terminal (screen), it is line buffered. When the output of your program goes to a pipe, it is fully buffered. You can control the buffering mode by … Read more
You need: sprintf(Buffer,”Hello World”); sprintf(Buffer + strlen(Buffer),”Good Morning”); sprintf(Buffer + strlen(Buffer),”Good Afternoon”); and of course you need your buffer to be big enough.
Use vfprintf, like so: void Error(const char* format, …) { va_list argptr; va_start(argptr, format); vfprintf(stderr, format, argptr); va_end(argptr); } This outputs the results to stderr. If you want to save the output in a string instead of displaying it use vsnprintf. (Avoid using vsprintf: it is susceptible to buffer overflows as it doesn’t know the … Read more
You can use the following technique: printf(“%.*s”, 5, “=================”); This will print “=====” It works for me on Visual Studio, no reason it shouldn’t work on all C compilers.
If your printf supports the ‘ flag (as required by POSIX 2008 printf()), you can probably do it just by setting your locale appropriately. Example: #include <stdio.h> #include <locale.h> int main(void) { setlocale(LC_NUMERIC, “”); printf(“%’d\n”, 1123456789); return 0; } And build & run: $ ./example 1,123,456,789 Tested on Mac OS X & Linux (Ubuntu 10.10).
std::ostringstream Example: #include <iostream> #include <sstream> // for ostringstream #include <string> int main() { std::string name = “nemo”; int age = 1000; std::ostringstream out; out << “name: ” << name << “, age: ” << age; std::cout << out.str() << ‘\n’; return 0; } Output: name: nemo, age: 1000
By default output to stdout is line-buffered when connected to a terminal. That is, the buffer is flushed when it’s full or when you add a newline. However, if stdout is not connected to a terminal, like what happens when you redirect the output from your program to a file, then stdout becomes fully buffered. … Read more
The printf format specifier %zu will work fine on C++ systems; there is no need to make it more complicated.