Question

In C using Xcode, how to change the while loop to mach the first for loop?

#include <stdio.h>

int main (int argc, const char * argv[])
{
    int i;

    i = 0;
    while ( i++ < 4)
        printf ("while: i%d\n",i);

    printf ("after while  loop, i=%d\n\n", i );

    for (i = 0; i < 4; i++)
        printf ("first for: i=%d\n", i );

    printf ("after first loop, i=%d\n\n", i );

    for ( i= 1; i <=4; i++)
        printf ("second for: i=%d\n", i );

    printf ("after second loop, i=%d\n", i );

    return 0;
}

Answer 1

To change while loop to for loop:

for (i = 1; i < 5; ++i)
    printf ("while: i%d\n",i);

To make while loop print numbers like the for loop:

while ( i < 4 )
    printf ("while: i%d\n", i++);

Or alternatively:

while ( i < 4 )
{
    printf ("while: i%d\n", i);
    ++i;
}

Read about pre-increment vs post-increment to get the idea. For example, here.