'>'的左操作数是垃圾值

Question

当我构建并安装我的应用程序时,我会收到以下内存警告

"'>'的左操作数是一个垃圾值"在这一行isTrue =(newLength> 20)？否:是;

这里有什么问题.谢谢你的帮助

 (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string {
    NSUInteger newLength;
    BOOL isTrue;
    if(textField == txtFirstName){
        newLength = [textField.text length] + [string length] - range.length;
        //isTrue = (newLength > 20) ? NO : YES;
    }
    if(textField == txtLastName){
        newLength = [textField.text length] + [string length] - range.length;
        //isTrue = (newLength > 20) ? NO : YES;
    }
    if(textField == txtEmail){
        newLength = [textField.text length] + [string length] - range.length;
        //isTrue =  (newLength > 100) ? NO : YES;
    }
    if(textField == txtCompanyName){
        newLength = [textField.text length] + [string length] - range.length;
        //isTrue =  (newLength > 30) ? NO : YES;
    }
    if(textField == txtPassword){
        newLength = [textField.text length] + [string length] - range.length;
        //isTrue =  (newLength > 30) ? NO : YES;
    }
    if(textField == txtRe_EnterPassword){
        newLength = [textField.text length] + [string length] - range.length;
        //isTrue =  (newLength > 30) ? NO : YES;
    }
    if(textField == txtZipCode){
        newLength = [textField.text length] + [string length] - range.length;
        //isTrue =  (newLength > 20) ? NO : YES;
    }
    if(textField == txtCountry){
        newLength = [textField.text length] + [string length] - range.length;
        //isTrue =  (newLength > 30) ? NO : YES;
    }
    isTrue = (newLength > 20) ? NO : YES;

    return isTrue;
}

Answer 1

当所有if条件都失败时,即出现问题.如果textField不是您期望的那一组.

在这种情况下,newLength永远不会分配,并且将是随机垃圾值.虽然这可能"永远不会发生",但静态分析仪并未意识到这一点.

您应该初始化newLength为具有默认值,可能为零.