2nd line defines a multi-line macro. The slash at the end of line tells the preprocessor that the macro definition is continued on the next line. The preprocessor replaces any instance of the macro name by the macro definition. This process is called macro expansion and it occurs before compilation. After this stage the above code will become,
#include <stdio.h>
#define PRINT(i, limit) while (i < limit) \
{ \
printf("GeeksQuiz "); \
i++; \
} \
int main()
{
int i = 0;
while (i < limit) { printf("GeeksQuiz ");i++;}
return 0;
}
Therefore it prints "GeeksQuiz" three times.