cool

#include <stdio.h>                                                              
                                                                                
int f(int, int);                                                                
int g(int);                                                                     
int func(int, int);                                                             
                                                                                
int f(a,b)                                                                      
{                                                                               
        int a, b;                                                                                                                                             
                                                                                
        return a*b;                                                             
}                                                                               
                                                                                
int g(a)                                                                        
{                                                                               
        int a;                                                                  
                                                                                
        return -a+1;                                                            
}                                                                               
                                                                                
int func(a,b)                                                                   
{                                                                               
        int a, b;                                                               
        int c, d;                                                               
                                                                                
        return (c = a+b, d = f(a,c), g(d));                                     
}                                                                               
                                                                                
int main(void)                                                                  
{                                                                               
        printf("%d\n", func(3,4));                                              
}

===================================================

cc     a.c   -o a
a.c: In function ‘f’:
a.c:9:13: erreur: ‘a’ redeclared as different kind of symbol
         int a, b;
             ^
a.c:7:5: note: previous definition of ‘a’ was here
 int f(a,b)
     ^
a.c:9:16: erreur: ‘b’ redeclared as different kind of symbol
         int a, b;
                ^
a.c:7:5: note: previous definition of ‘b’ was here
 int f(a,b)
     ^
a.c: In function ‘g’:
a.c:16:13: erreur: ‘a’ redeclared as different kind of symbol
         int a;
             ^
a.c:14:5: note: previous definition of ‘a’ was here
 int g(a)
     ^
a.c: In function ‘func’:
a.c:23:13: erreur: ‘a’ redeclared as different kind of symbol
         int a, b;
             ^
a.c:21:5: note: previous definition of ‘a’ was here
 int func(a,b)
     ^
a.c:23:16: erreur: ‘b’ redeclared as different kind of symbol
         int a, b;
                ^
a.c:21:5: note: previous definition of ‘b’ was here
 int func(a,b)
     ^