Programmation en C

Voici ce je propose:

#include<stdio.h>
#include<math.h>
#include<conio.h>
long smd;
long mtc;
long bd, bc, bdx, bm, nvmtc;
int rest1, rest2, rest3;
main()
{
long nbd,nbc, nbdx, nbm;
nbd=50;
nbc=300;
nbdx=1000;
nbm=3000;
mtc=nbd*10000+nbc*5000+nbdx*2000+nbm*1000;
printf("Entrez la somme demand'e:\n");
scanf("%d",&smd);
int mm;
mm=smd%1000;
if(mm==0 && smd<mtc)
{
bd=smd/10000;
rest1=smd%10000;
bc=rest1/5000;
rest2=rest1%5000;
bdx=rest2/2000;
rest3=rest2%2000;
bm=rest3/1000;
nbd=nbd-bd;
nbc=nbc-bc;
nbdx=nbdx-bdx;
nbm=nbm-bm;
printf("Reste de billets %d de 10000 %d de 5000 %d de 2000 %d de 1000.\n", nbd, nbc, nbdx, nbm);
printf("Vous aurez %d billet de 10000 %d billet de 5000 %d billet de 2000 %d billet de 1000:\n", bd, bc, bdx, bm);
nvmtc=mtc-smd;
printf("Votre nouveau solde est de %d:\n", nvmtc);
}
else
{
printf("Paiement impossible.\n");
}
getch();
return 0;
}