#include <stdio.h>
#include <stdlib.h>

int main(void)
{
    char chaine[20];
    int i;

    gets(chaine);
    while (chaine[i]!='\0') {
        printf("%c",chaine[i]);
        printf("%d",chaine[i]);
        i++;
    }
}

||=== Build: Release in exo_5 (compiler: GNU GCC Compiler) ===|
G:\TP4\exo_5\main.c||In function 'main':|
G:\TP4\exo_5\main.c|15|warning: control reaches end of non-void function [-Wreturn-type]|
G:\TP4\exo_5\main.c|10|warning: 'i' is used uninitialized in this function [-Wuninitialized]|
||=== Build finished: 0 error(s), 2 warning(s) (0 minute(s), 0 second(s)) ===|