Your question title copied into google gives "About 3,310,000 results (0.38 seconds)" - even with the spelling oversight.
Simply put, c & c++ compile to machine instructions that are specific to a particular architecture.
Consider the following source-code:
#include <cstdio>
int main()
{
printf("Hello World");
}
If I compile it for Arm Cortex-M3, Intel x86, Atmel ATMega, Motorolla 68000 it will produce different machine code. The output from the compiler will be very different in each case - yet clearly, the output of the program will be identical.
Java or HTML for instance, use the exact same code regardless of what you run it on. It's just the Java Virtual Machine or the Browser that are platform dependant. Yet, if written in c/c++, they can be compiled for each target platform with little or no modification.