Re: One question of C

drazet wrote:


why the answer is 12 13 13?

[code]

#include <stdio.h>
int x;
int m1(void);
int c1(int x);

int main(void){
int x= 10;

This 'x' shadows the global 'x' while it's in scope. Bad idea.

x++;

Local 'x' is now 11.

c1(x);

Local 'x' is still 11 since c1 gets, and acts on it's own copy of 'x'.
You also discard it's return value.

x++;

Local 'x' is now 12.

m1();

m1 updates the global 'x' and adds 10 to it.
Global 'x' is now 10.

printf("%d\t",x);

This prints the value of the local 'x', i.e., 12.

x++;

And increment it to 13.

c1(x);

Once more c1 gets it's own copy of main's 'x' and increments it by one
and returns that value, which you discard once again.

printf("%d\t",x);

Local 'x' is printed again, i.e., 13.

m1();

Global 'x' is incremented by 10 again.

printf("%d\n",x);

Once more local 'x' is printed, i.e., 13.

return 0;
}

int m1(void){
return (x+=10);

Here 'x' refers to the global object of that name.

}

int c1(int x){
return (x+=1);
}

[code end]


.

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