#include<stdio.h>
void exchange(void);
int a, b; /* declaration of global variables */
int main()
{ /* main program starts here...*/
a = 5;
b = 7;
printf(" In main: a = %d, b = %d\n", a, b);
exchange(); /* function call, no parameters are passed */
printf("\n Back in main: ");
printf("a = %d, b = %d\n", a, b);
return 0;
} /* main program ends here */
void exchange(void)
{ /* function body starts here...*/
int temp; /* decl. of local variable in function*/
printf("\n In function exchange() before change: just received from\
main... a=%d and b=%d",a,b);
temp = a;
a = b;
b = temp; /* interchange over */
printf("\n In function exchange() after change: ");
printf("a = %d, b = %d\n", a, b);
} /* function body ends here*/
In main: a = 5, b = 7
In function exchange() before change: just received from main... a=5 and
b=7
In function exchange() after change: a = 7, b = 5
Back in main: a = 7, b = 5
First understand the algorithm carefully. Then study the program line-by-line and compare it with the output. Finally, review the explanation section to strengthen your logic and programming understanding.
Rewrite the program without looking at the code. Modify values, conditions or logic and run it again. This helps improve confidence and strengthens coding skills much faster.