# include 
# include 
Void f1 (int a, b int, int) c; 
Void f2 (int a, b int, int) c; 
Void f3 (int a, b int, int) c; 
Int main () 
{
int a,b,c; 
Double t; 
Printf (" please enter a b c \ n "); 
The scanf (" % d % d % d ", & amp; A, & amp; B, & amp; c); 
Printf (" the original equation for dx ^ 2 dx + + % % % d=0 \ n ", a, b, c); 
T=b * * a * b - 4 c. 
If (t> 0) 
{
F1 (a, b, c); 
} 
If (t==0) 
{
F2 (a, b, c); 
} 
If (t<0) 
{
F3 (a, b, c); 
} 
return 0; 
} 
Void f1 (int a, b int, int) c 
{
Double x1, x2, t; 
T=b * * a * b - 4 c. 
X1=(a - b + SQRT (t))/(2 * a); 
X2=(a - b - SQRT (t))/(2 * a); 
Printf (" x1=% f, x2=% f ", x1, x2); 
} 
Void f2 (int a, b int, int) c 
{
Double x1, x2, t; 
T=b * * a * b - 4 c. 
X1=(a - b + SQRT (t))/(2 * a); 
X2=x1; 
Printf (" x1 x2==% f ", the x1); 
} 
Void f3 (int a, b int, int) c 
{
Printf (" no real root \ n "); 
} 

 # include & lt; Stdio. H> 
Int main () 
{
Int judge (int n); 
int x; 
Printf (" input a integer: "); 
The scanf (" % d ", & amp; X); 
If (judge (x)) 
Printf (" % d is a prime \ n ", x); 
The else 
Printf (" % d is not a prime \ n ", x); 
return 0; 
} 
Int judge (int n) 
{
Int I, k=n/2; 
If (n==1) 
return 0; 
for(i=2; i<=k; I++) 
If I (n %==0) 
return 0; 
return 1; 
} 

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