0 #include <stdio.h>

1 #include <string.h>

2 void pal ( char c [ ] , int k , int n ) {

3 if ( k == n || n - k == 1 ) {

4 return 1 ; }

5 if ( c [ k ] == c [ n ] ) {

6 return pal ( c , k + 1 , n - 1 ) ; }

7 else {

8 return 0 ; } }

9 int main ( ) {

10 char s [ 100 ] ;

11 int a = getchar ( ) ;

12 int i = 0 ;

13 while ( a != ' \0 ' ) {

14 s [ i ] = a ;

15 i ++ ;

16 a = getchar ( ) ; }

17 if ( pal ( s , 0 , i - 1 ) ) {

18 printf ( " Yes " ) ; }

19 else {

20 printf ( " No " ) ; }

21 return 0 ; }

Diagnostic Feedback：17：void value not ignored as it ought to be

The results generated by DrRepair：

pred err line#: 17

pred_code_candidate: if ( pal ( s , 0 , i - 1 ) ) {

pred_code_candidate: if ( pal ( s , 0 , n - 1 ) ) {

pred_code_candidate: if ( pal ( s , 0 , i - 1 ] ) {

pred_code_candidate: if ( pal ( s , 0 , n , 1 ) ) {

all edit candidates rejected.

The results generated by TransRepair：

pred err line#: 2 √

pred_code_candidate: int pal ( char c [ ] , int k , int n ) {√

pred code (edit): int pal ( char c [ ] , int k , int n ) { √

This example is used for palindrome checking. If the input string is a palindrome, then the program prints "Yes", otherwise prints "No". Line 17 needs a return value for if conditional judgment, however, the function is declared as "void" at line 2. Hence, a correct repaired statement is to fix the function declaration from "void pal (char c[], int k, int n)" to "int pal (char c[], int k, int n)". We can find that the result provided by TransRepair is correct. It not only predicts the position of the "true" error statement but also generates a correct fixing.

0 #include <stdio.h>

1 #include <stdlib.h>

2 void replace_substring ( char * s , int m , char * t , char * w , int r , int i ) {

3 int j ;

4 for ( j = i ; j < i + m ; j ++ ) {

5 s [ j ] = w [ j - i ] ; }

6 for ( j = i + m ; j < m + r ; j ++ ) {

7 s [ j ] = t [ j ] ; } }

8 int main ( ) {

9 int m , n , r , i , j , c = 0 ;

10 char * s , * t , * w , * p ;

11 scanf ( " %d " , & m ) ;

12 s = ( char * ) malloc ( sizeof ( char ) * ( m + 100 ) ) ;

13 t = ( char * ) malloc ( sizeof ( char ) * ( m + 100 ) ) ; 14 for ( i = 0 ; i < m ; i ++ ) {

15 scanf ( " %c " , & s [ i ] ) ;

16 t [ i ] = s [ i ] ; }

17 scanf ( " %d " , & n ) ;

18 w = ( char * ) malloc ( sizeof ( char ) * n ) ;

19 for ( i = 0 ; i < m ; i ++ ) {

20 scanf ( " %c " , & s [ i ] ) ; }

21 scanf ( " %d " , & r ) ;

22 p = ( char * ) malloc ( sizeof ( char ) * r ) ;

23 for ( i = 0 ; i < m ; i ++ ) {

24 scanf ( " %c " , & s [ i ] ) ; }

25 for ( i = 0 ; i < m ; i ++ ) {

26 if ( s [ i ] == p [ 0 ] ) {

27 for ( j = i ; j < ( i + n ) ; j ++ ) {

28 if ( s [ i ] == p [ j - i ] ) {

29 c ++ ; } }

30 if ( c == n ) {

31 replace_substring ( s , t , w , i ) ;

32 i = i - r ; }

33 c = 0 ; } }

34 printf ( " %s " , s ) ;

35 return 0 ; }

Diagnostic Feedback：31：too few arguments to function ‘replace_substring’

The results generated by DrRepair：

pred err line#: 31 √

pred_code_candidate: replace_substring ( s , t , w , i ) ;

pred_code_candidate: replace_substring ( s , r , w , i ) ;

pred_code_candidate: replace_substring ( s , m , w , i ) ;

pred_code_candidate: replace_substring ( s , r , w , w , i ) ;

pred_code_candidate: replace_substring ( s , t , w , w , w ) ;

all edit candidates rejected.

The results generated by TransRepair：

pred err line#: 31 √

pred_code_candidate: replace_substring ( s , m , t , w , r , i ) ; √

pred code (edit): replace_substring ( s , m , t , w , r , i ) ; √

This example is used to replace a substring. The invoked function replace_substring requires six parameters, however in the main function, only four parameters are given at line 31. Hence, to fix this error, a correct number of parameters should be used. We can see that although the predicted location is correct for both models, the first candidate that TransRepair generates is already correct and pass the compiler check. It demonstrates that TransRepair has more learning capacity thann DrRepair in fixing program errors.