This program prints "Hola mundo" 100 times. It works in Python, C and Brainfuck.

multilang

#define is_C 1
#ifndef is_C
#>++++[<+++++++++++++++++++++++++>-]<[>>[-]>++++[<++++++++++++++++++>-]
#<.>+++++[<++++++++>-]<-.---.-----------.[-]>++++[<++++++++>-]<.>+++++++
#[<+++++++++++>-]<.++++++++.-------.----------.+++++++++++.[-]++++++++++.<<-]
#[-][
def principal():
    return
def semicolon():
    return
def print_s(s):
    print s
def int_a():
    return
#endif
#include <stdio.h>
#define principal() main(){
#define int_a() int a = 0;
#define semicolon() ;
#define pass }
#define print_s(x) printf("%s\n",x);
principal()
int_a()
a = 100
semicolon()
#ifndef is_C
"""
# "
#endif
while(a>0){
 
#ifndef is_C
"""
# "
#endif
#ifndef is_C
while(a > 0):
#endif
    print_s("Hola mundo")
    a-=1
    semicolon()
    pass
pass
#ifndef is_C
#]
#endif