NSString *tempA = @"123";

 NSString *tempB = @"456";


1,字符串拼接

NSString *newString = [NSString stringWithFormat:@"%@%@",tempA,tempB];


2,字符转int

int intString = [newString intValue];


3,int转字符

NSString *stringInt = [NSString stringWithFormat:@"%d",intString];


4,字符转float

float floatString = [newStringfloatValue];


5,float转字符

NSString *stringFloat = [NSString stringWithFormat:@"%f",intString];