After I input "step", gdb will not go into the function for debugging.

I entered "step" and gdb won't go into the function to debug-Linux general technology-Linux technology and application information. The following is a detailed description. I typed "step", but gdb did not step into the specified function.
After I input "step", gdb will not go into the function for debugging.
The code is:
Code:

# Include "file. h"
# Include "WordAnalyze. h"
# Include "OperatorPriorAnalyze. h"
# Include
# Include

Using namespace std;

Int main (int argc, char ** argv ){
Unsigned int size;
Char * mem;
Char * line;
Char tc [100];
File f1;
OperatorPriorAnalyze operator_analyze;
WordAnalyze w1;
Size = f1.readfile ("./test.txt", & mem );
W1.setSource (mem );
W1.setSize (size );
While (! W1.atEnd ()){
Unsigned int I = w1.getLineSize ();
Line = w1.getLine (); // gdb can enter the internal function of getLine ().
Operator_analyze.setSize (I); // But gdb does not enter the getSize () Internal
Operator_analyze.setSource (line); // it will not enter
Unsigned int k = 0;
While (k Tc [k] = line [k];
K ++;
}
Tc [k] = '\ 0 ';
Cout <tc;
Operator_analyze.restart ();
If (operator_analyze.Judge () = 0)
Cout <"Right! "<Endl;
Else
Cout <"Wrong! "<Operator_analyze.getError () <endl;
Delete line;
}
Return 0;
}
Type "step". It seems that gdb will not enter functions in the "operator_analyze" class and can enter other functions.
Can anyone explain to me?
However, if you keep entering stepi, you can enter the function. Help !!
Thanks!