Compile a C/C++ program without make, but using a simple header that is valid in both C/C++ and (ba)sh.

autocompile.cpp

#if 0
# Run this file with bash to compile the C++ program.

CC=g++
FLAGS=

# Output file will have the same name of this file without extension
OUT_FILE=${BASH_SOURCE%.cpp}

# Ensure we are not overwriting
if [ -f "$OUT_FILE" ]; then
    read -n 1 -p "File exists, overwrite? [y/N]" yn
    case $yn in
        [Yn]* ) echo;;
        * ) exit;;
    esac
fi

# Compile
echo "Compiling to $OUT_FILE"
$CC $BASH_SOURCE -o $OUT_FILE $FLAGS

exit
#endif

#include <iostream>

int main(int argc, char *argv[]) {
    std::cout << "Hello, World!\n";
    return 0;
}