How can I implement a 'Do while' loop only using GOTO in the C language?

do{
    // Some code 
}
while (condition);

is equal to:

label:
{
     // Some code
}
if(condition) goto label;

A do-while loop is a variation of a while loop. The condition is checked by a while loop and statements are in the do segment.

The do while loop checks the condition at the end of the loop. This means that the statements inside the loop body will be executed at least once even if the condition is never true.

The variable within the scope of the loop. I.e. you need to be within the loop to access it. It's the same as if you declared a variable within a function, only things in the function have access to it.

do{
    statement(s);
}while(condition);

Instead of using a for, while, or do while loop, you can do the same job using goto. Like this:

int i = 0;

firstLoop:
    printf("%d", i);
    i++;
    if(i<10)
        goto firstLoop;
    printf("\nout of first loop");

But it is suggested not to use goto statements. The goal you achieve by using goto statement, can be achieved more easily using some other conditional statements like if-else, etc.

It is easy to do.

For starters you should take into account that the body of the do-while statement forms a block scope even if the body is not represented by a compound statement. For example this program is correct.

#include <stdio.h>

int main(void) 
{
    struct A
    {
        int s;
    };
    
    do
        printf( "sizeof( struct A { int x; int y; } )  = %zu\n", 
                sizeof( struct A { int x; int y; } ) );
    while ( sizeof( struct A ) == 8 );
    
    printf( "sizeof( struct A  )  = %zu\n", 
            sizeof( struct A ) );
    
    return 0;
}

The program output is

sizeof( struct A { int x; int y; } )  = 8
sizeof( struct A  )  = 4

That is the structure A declared in the sub-statement of the do-while statement is in its own inner scope relative to the scope where the do-while statement is written and where the structure A with one data member is defined. And each time when the sub-statement gets the control the structure A is declared anew.

The rewritten do-while statement using a goto statement will look the following way as it is shown in the demonstration program below. In this case you need to use a compound statement to introduce the inner scope.

#include <stdio.h>

int main(void) 
{
    struct A
    {
        int s;
    };
    
    L1:
    {
        printf( "sizeof( struct A { int x; int y; } )  = %zu\n", 
                sizeof( struct A { int x; int y; } ) );
    }
    
    if ( sizeof( struct A ) == 8 ) goto L1;
    
    printf( "sizeof( struct A  )  = %zu\n", 
            sizeof( struct A ) );
    
    return 0;
}