stringByReplacingOccurrencesOfString：withString：

Question

嗨，我是Objective C的新手，但我没有使用正在compileonline.com上提供的在线编译器的Mac。 今天我写了下面的程序

 1 #import<Foundation/Foundation.h>
 2 int main(){
 3   NSAutoreleasePool * pool = [[NSAutoreleasePool alloc]init];
 4   NSString * firstName = @"Eric";
 5   NSString * lastName  = @"Simmons";
 6   NSString * fullName = [[firstName stringByAppendingString: @" "]stringByAppendingString: lastName];
 7   NSLog(fullName);//prints Eric Simmons
 8   NSLog (@"The Entered full name is :",fullName);// Just prints The entered full name is : 
 9   NSString * correctFullName = [fullName stringByReplacingOccurrencesOfString: firstName withString: @"Derrick"];
 10  NSLog(correctFullName);//prints Derrick Simmons
 11   NSLog(@"The correct full name : ",correctFullName);// Just prints The correct full name is : 
 12  [pool drain];
 13   return 0;
 14 }

但是，此程序效果很好。 但是输出不是我期望的。 输出看起来像这样

Executing the program....
2014-01-02 05:42:27.958 demo[18115] Eric Simmons
2014-01-02 05:42:27.959 demo[18115] The Entered full name is :
2014-01-02 05:42:27.959 demo[18115] Derrick Simmons
2014-01-02 05:42:27.959 demo[18115] The correct full name : 

当执行第8行和第11行时，不会打印名称。 我哪里出错了。 是程序错误还是编译器错误。 请帮忙...

Answer 1

在第8和11行中，您忘记了格式说明符

NSLog (@"The Entered full name is : %@",fullName);
NSLog(@"The correct full name : %@",correctFullName);

Answer 2

您需要格式说明符才能打印字符串。

使用％@打印字符串，如下所示：

 NSLog (@"The Entered full name is : %@",fullName);