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in Technique[技术] by (71.8m points)

c - how to make "i+=x" works as "i++"?

The following code

int i=0;
while(i<10) {
   printf("%d
", i++);
}

is equivalent to

int i=0;
while(i<10) {
   printf("%d
", i); i++;
}

But the following code

int i=0;
while(i<10) {
   printf("%d
", i+=2);
}

is equivalent to

int i=0;
while(i<10) {
   i+=2; printf("%d
", i);
}

How to make it equivalent to

int i=0;
while(i<10) {
   printf("%d
", i); i+=2;
}

the same as i++

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1 Reply

0 votes
by (71.8m points)

You can write a macro to do this too. Like this:

#define POSTINC(var, val) ((var) += (val), (var) - (val))

printf("%d
", POSTINC(i,2));

But better use either for or just increase the value in the next statement.


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