how to get the complete source code location corresponding to the ASTnode in clang - syntax

Question

i am using clang plugin to develop a tool which can insert a 'printf' statemente behind every statement to trace the project.for example:
int main(){
int a=1000;
if(a==1000){
a=999;}
}
insert a 'printf' statemente
int main(){
int a=1000;
printf("int a=1000;");
if(a==1000){
a=999;
printf("a=999;");}
}
i use the structure of the 'printFunctionName' in the clang'example to realize.
i need to get the complete source code location corresponding to the ASTnode so that i can insert the 'printf' statement in the right location.however i found i can't use the Stmt->getSourceRange() function to get the complete location range for some Specific type statement.for example,BinaryOperator,UnaryOperator.
a=1000;
| | | |-BinaryOperator 0x565356502960 <line:13:3, col:5> 'int' '='
| | | | |-DeclRefExpr 0x565356502918 <col:3> 'int' lvalue Var 0x565356502880 'a' 'int'
| | | | `-IntegerLiteral 0x565356502940 <col:5> 'int' 1000
In fact, these characters occupy 5 columns in the source code file, but only 3 columns are recognized.
a++;
-UnaryOperator 0x5653565029b0 <line:14:9, col:10> 'int' postfix '++'
| | | | `-DeclRefExpr 0x565356502988 <col:9> 'int' lvalue Var 0x565356502880 'a' 'int'
this is three chars for 3 column.but clang think it is 2 column.
do you have some idea to solve this problem?and coud you please give me some advices to better recognize the location for a complete sentence end with ';'?thank you!
and this is my code:
SourceRange range=declStmt->getSourceRange();
TheRewriter.ReplaceText(declStmt->getSourceRange(),str+";"+"\nprintf(\""+str+"\\n\")");